For most of the season, we've focused on the new No. 1 team in a given week. Given that we've had five different No. 1 teams in the Power Rankings and six different No. 1 teams in the AP poll, there have been plenty of things to discuss at the top of the rankings.

This week, however, the big story is the newest arrival inside the top five: San Diego State. The Aztecs are one of two unbeatens remaining in college basketball, and they improved to 15-0 on Saturday after winning at Utah State -- arguably their toughest game left on the schedule. Brian Dutcher's team gets the edge on Auburn, the other unbeaten team, for the No. 5 spot due to the Aztecs' collection of quality wins. They now own victories over Iowa, Creighton, BYU and Utah State, compared to Auburn's best win coming against NC State.

Now there are two big questions. One, can San Diego State go the rest of the regular season without a loss? Two, is San Diego State really that good?

According to KenPom, San Diego State will be favored in every game the rest of the way, with the toughest test coming at Nevada in the final game of the season. KenPom gives the Aztecs a 6.2% chance of finishing the regular season with an unbeaten record. ESPN's Basketball Power Index also projects San Diego State's toughest remaining game to come at Nevada, giving the Aztecs a 61.7% chance of winning that game. Meanwhile, BartTorvik.com projects the Aztecs to finish 28-1 -- but also has them being favored by single digits just once the rest of the way.

So yes, San Diego State running the table is clearly within the range of outcomes.

Now, how good is San Diego State? The Aztecs are one of the best defensive teams in the country, holding all but three teams below one point per possession. They're fifth in scoring defense and eighth in field goal percentage defense. Offensively, they really shoot it from 3-point range and take care of the ball -- and have a legitimate go-to guy in former Washington State transfer Malachi Flynn. Flynn, Yanni Wetzell (Vanderbilt) and KJ Feagin (Santa Clara) are all mainstays in the starting lineup after transferring in from other programs.

Last season, Nevada was one of the final unbeatens and started 24-1 before losing four of its final nine games and getting bounced in the first round of the NCAA tournament. Compared to that Nevada team, this San Diego State group was far more battle-tested in the nonconference and also shoot from the perimeter and defend more effectively.

Here's my take: San Diego State is good enough to hover around the top five for the rest of the season and push for a 1-seed on Selection Sunday.

1. Gonzaga Bulldogs (16-1)

Previous ranking: 1

This week: at San Diego (Thursday), at Loyola Marymount (Saturday)

Gonzaga remains atop the rankings -- but the Bulldogs didn't make it easy on themselves. They were down at halftime to Portland, and then hung on in the final seconds against Pepperdine. Mark Few's team had its worst offensive performance since the loss to Michigan against Pepperdine, but it's unlikely the Zags are going to have too many off nights at that end of the floor. However, the defensive side of the ball has shown some signs of concern. It has allowed more than one point per possession four times this season, and its raw defensive efficiency is ranked outside the top 80 nationally at KenPom. Issues defending the 3-point shot have crept up in several games thus far.

2. Duke Blue Devils (13-1)

Previous ranking: 2

This week: at Georgia Tech (Wednesday), vs. Wake Forest (Saturday)

There's an argument to be made that freshman big man Vernon Carey Jr. has been the most dominant player in college basketball over the past two months, but Mike Krzyzewski should also be excited about the recent performance from Carey's classmate, Matthew Hurt. Hurt entered college as a top-tier prospect but was very inconsistent during the nonconference portion of the season. Over the past two games, though, Hurt has totaled 38 points and went 6-for-12 from 3-point range. He hit five 3s against Boston College, and then had six rebounds, four assists, two blocks and three steals at Miami. Hurt could give the Blue Devils a viable third option after Carey and Tre Jones.

3. Baylor Bears (11-1)

Previous ranking: 3

This week: at Texas Tech (Tuesday), at Kansas (Saturday)

This is going to be a statement week for Baylor in its quest for a Big 12 title. The Bears are guarding as well as anyone in America, but the offense is going to be put to the test against Texas Tech and Kansas. Both the Red Raiders and Jayhawks are generally two of the best defensive teams in the country, and Baylor has struggled at times to score against good teams this season. The Bears are going to need big efforts from the backcourt of Jared Butler and MaCio Teague, especially from behind the arc. Some offensive balance on the interior would provide a big boost, but Freddie Gillespie has been inconsistent since hitting double figures in the first four games of the season, and Tristan Clark is still not 100%.

4. Kansas Jayhawks (11-2)

Previous ranking: 4

This week: at Iowa State (Wednesday), vs. Baylor (Saturday)

The emergence of freshman Christian Braun was something not many people saw coming this season. The in-state recruit wasn't highly touted coming out of high school, and his usage the first few weeks wasn't surprising. He had played extended minutes in blowouts, but things changed in the loss at Villanova. Braun came off the bench to play 16 minutes and provided a spark on the offensive end. He then scored nine points against Stanford, and played 30 minutes, grabbed five rebounds and scored six points against West Virginia over the weekend. He gave Kansas some toughness and has established himself as a key part of Bill Self's rotation.

Alan Smith/Icon Sportswire

5. San Diego State Aztecs (15-0)

Previous ranking: 7

This week: at Wyoming (Wednesday), vs. Boise State (Saturday)

We hit on San Diego State above, but let's dig in on Malachi Flynn a little bit. The former Washington State guard should have been one of the most sought-after sit-out transfers two springs ago after putting up impressive numbers in the Pac-12, but only a handful of power-conference programs came calling. After redshirting last season, Flynn has been one of the best guards in the country, putting up even better numbers than he did at Washington State. In a huge road win over Utah State over the weekend, he went toe-to-toe with Aggies star Sam Merrill and finished with 22 points, five rebounds and four assists.

6. Auburn Tigers (13-0)

Previous ranking: 6

This week: vs. Vanderbilt (Wednesday), vs. Georgia (Saturday)

San Diego State's unbeaten run is getting more hype than Auburn's own undefeated record, mostly because the Aztecs have a far better chance of finishing the regular season without a loss. But there are also some questions about Bruce Pearl's team due to its schedule thus far; Auburn is the only team in the top 65 of the NET that hasn't even played a Quadrant 1 game yet this season. That should change next week when they travel to Alabama and Florida, but before then, the Tigers are heavily favored to rack up a couple of more wins. Beware of Georgia, though: The Bulldogs just went into Memphis and beat Penny Hardaway's club despite an off night from Anthony Edwards.

7. Butler Bulldogs (14-1)

Previous ranking: 9

This week: at Providence (Friday)

It has been an interesting few weeks for star guard Kamar Baldwin. After looking like one of the best guards in the country through the first five weeks of the season, Baldwin then had a three-game stretch in which he totaled 10 points on 4-for-28 shooting. He bounced back against St. John's for 19 points and five 3-pointers, but suffered an ankle injury while Butler nearly collapsed down the stretch. Against Creighton over the weekend, Baldwin had a scoreless, 0-for-9 first half -- before rebounding for 20 second-half points. Baldwin now gets a few days to rest the ankle before a difficult four-game stretch that includes three road games and showdowns with Seton Hall and Villanova.

8. Oregon Ducks (12-3)

Previous ranking: 5

This week: vs. Arizona (Thursday), vs. Arizona State (Saturday)

Oregon never wins at Colorado, so its loss to the Buffaloes on Thursday wasn't all that surprising, although it was nice to see the Ducks bounce back and get a win at Utah over the weekend. But Dana Altman's team -- one of the top 10 teams in the country in 3-point shooting -- has now seen its perimeter prowess disappear in two of its three losses this season. The Ducks were 3-for-18 from 3 against Colorado, and Anthony Mathis made one 3-pointer and had just seven points. Mathis, the New Mexico graduate transfer and one of the better shooters in the Pac-12, is 2-for-13 from 3 and is averaging 4.0 points in Oregon's three losses. In the Ducks' wins, he's shooting 55.6% from 3 and averaging 11.3 points.

9. Florida State Seminoles (13-2)

Previous ranking: In the waiting room

This week: at Wake Forest (Wednesday)

Another year, another season in which the country underestimates Florida State. The Seminoles were terrific against Louisville over the weekend, with the perimeter trio of M.J. Walker, Trent Forrest and Devin Vassell consistently making plays. Leonard Hamilton's team now has wins away from Tallahassee against Louisville, Purdue, Florida and Tennessee. The Noles have won six in a row and should be favored in each of their next four games. How have they done it this season? Pretty much the same way Hamilton has always done it: with size and depth. Florida State is the tallest team in the country by average height and ranks in the top 40 nationally in bench minutes.

10. West Virginia Mountaineers (11-2)

Previous ranking: 11

This week: at Oklahoma State (Monday), vs. Texas Tech (Saturday)

Heading into West Virginia's two-game stretch against Ohio State and Kansas, we said it was time to figure out whether the Mountaineers are for real. They certainly answered that question. They beat Ohio State on a neutral court in Cleveland, then hung with Kansas for 40 minutes in Lawrence before falling late. Perhaps the most impressive part of the effort against the Jayhawks was freshman Oscar Tshiebwe holding his own against Udoka Azubuike and Kansas. Tshiebwe finished with 17 points, 17 rebounds and two blocks. But Bob Huggins' team is going to need to find ways to manufacture offense outside of offensive boards and free throws; it can go through scoring lulls.

11. Ohio State Buckeyes (11-3)

Previous ranking: 8

This week: at Maryland (Tuesday), at Indiana (Saturday)

Suddenly, Ohio State is in a gut-check stretch of its season. The Buckeyes have dropped three of their last five games after starting the season with nine straight wins, and head on the road to Maryland and Indiana in their next two games. After a home game against Nebraska, they then go back on the road to face Penn State. So what's going on with Chris Holtmann's team? Simply put, the offense is struggling to create easy offense. Freshman DJ Carton, who made plays late against Kentucky two weeks ago, has totaled three points, three assists and nine turnovers the past two games. Starting point guard CJ Walker has two assists and five turnovers and scored four points against Wisconsin. The offense is heavily reliant on Kaleb Wesson, but someone else needs to step up.

12. Kentucky Wildcats (10-3)

Previous ranking: 15

This week: at Georgia (Tuesday), vs. Alabama (Saturday)

All eyes are on the status of point guard Ashton Hagans, who left Saturday's win over Missouri late -- although John Calipari said it was an ankle injury, as opposed to an Achilles. On the plus side, Calipari is getting a continued resurgence from big man Nick Richards and sophomore guard Immanuel Quickley. Richards has been dominant at times over the past two games, notching back-to-back double-doubles after finishing with 21 points, 12 rebounds and four blocks on Saturday. Quickley has provided a huge boost to Kentucky's perimeter production, totaling 41 points and six 3-pointers off the bench the past two games. If Kentucky gets the recent version of those players -- in addition to Tyrese Maxey and a healthy Hagans -- the Wildcats are going to be a tough out.

13. Michigan State Spartans (12-3)

Previous ranking: In the waiting room

This week: vs. Minnesota (Thursday), at Purdue (Sunday)

And here comes the Spartans. Michigan State, the consensus preseason No. 1 team in the country, has now run off seven straight wins after blowing out Michigan on Sunday afternoon. Cassius Winston is rounding into form, putting forth a masterclass performance against the Wolverines: 32 points and nine assists. Winston has now scored 20-plus points in four straight games and is showing why he was the preseason favorite to win the Wooden Award. But Xavier Tillman has established himself as the Robin to Winston's Batman, contributing in all facets of the game. Michigan didn't have an answer for him, as he finished with 20 points, 11 rebounds, three assists and six blocks.

14. Penn State Nittany Lions (12-2)

Previous ranking: In the waiting room

This week: at Rutgers (Tuesday), vs. Wisconsin (Saturday)

The Nittany Lions are for real, folks. If not for blowing a 21-point lead against Ole Miss back in November, Pat Chambers' team would likely be among the top 10 teams nationally. They own key wins over Maryland and Iowa, plus solid victories against Georgetown, Yale, Alabama and Syracuse. Penn State overcame a 34-point, 12-rebound effort from Iowa's Luka Garza on Saturday, buoyed by another stellar performance from St. Bonaventure transfer Izaiah Brockington. After failing to establish himself with the Bonnies, Brockington has emerged as one of the best sixth men in the Big Ten. He had 23 points against Iowa, the sixth time in seven games he has hit double figures.

15. Maryland Terrapins (12-2)

Previous ranking: 16

This week: vs. Ohio State (Tuesday), at Iowa (Friday)

A few weeks ago, Tuesday's showdown against Ohio State in College Park looked like it was going to be one of the games of the season in the Big Ten. Since then, the Terrapins have lost twice, the Buckeyes have lost three times and it's not clear either team is the Big Ten favorite. If the Terps are going to reach their potential this season, they need Jalen Smith to play like he did against Indiana over the weekend (19 points and eight rebounds in just 17 minutes). Smith finished last season on a tear and looked like a potential All-American this season, but he has been inconsistent over the past several weeks. Mark Turgeon needs him to be a dominant force down low.

16. Louisville Cardinals (11-3)

Previous ranking: 12

This week: vs. Miami (Thursday), at Notre Dame (Saturday)

The Cardinals barely remain in the rankings after a home loss to Florida State, their third loss in five games. Outside of a road trip to Duke on Jan. 18, the next two months appear to be a little easier for the Cardinals -- but Louisville will have to figure things out defensively in order to start rattling off wins again. The Cardinals allowed more than 1.1 points per possession in each of the past two games, losses to Kentucky and Florida State. Both opponents shot better than 46% from 3-point range and grabbed at least one-third of their misses. Chris Mack is considered one of the best defensive coaches in the country, so it's unlikely the recent issues become a trend -- but it's something to watch.

Dropped out: Memphis (10), Villanova (13), Michigan (14)

In the waiting room

Wichita State: The Shockers can make an AAC statement this week when they play host to Memphis on Thursday. There's no clear-cut favorite in the league, with Wichita, Memphis and Houston all looking the part so far. A win over the Tigers could get Wichita State into the Power Rankings, as the Shockers have just a loss to West Virginia in the negative column thus far.

Dayton: The Flyers aren't too far from getting back into the rankings, as their metrics are just too impressive to ignore. They're ranked in the top 10 of the NET, the BPI and at KenPom, and their only two losses thus far came in overtime against Kansas and Colorado, by a combined eight points. Obi Toppin is still performing like a Wooden Award candidate, too.

Memphis: The Tigers' overall resume probably wasn't worthy of a top-10 ranking in the first place, and their home loss to Georgia sends them plummeting out of the rankings. The loss did come without D.J. Jeffries, the team's second-leading scorer and rebounder. They'll have a big opportunity to get back in the mix this week, with an AAC showdown against Wichita State.