Perfection is a difficult standard. Only one team in the AP Top 25 remains unbeaten. And perfection is even more difficult to maintain in the week-to-week grind of conference play that dominates the depths of winter in college basketball.

Among conferences eligible for mid-major consideration, and excluding an Ivy League that is only one round into its schedule, we're already down to a mere 21 teams unbeaten in conference play -- out of nearly 300. The list of those slipping from among the conference unbeaten includes the top four teams from our previous rankings. That allows South Dakota, which lost the first conference game it played in 2019, to climb back to No. 1.

Facing a double-digit deficit in the fourth quarter of a conference game isn't the most direct route to reclaiming the No. 1 spot, but it worked for South Dakota. The Coyotes trailed Oral Roberts by 10 points on the road last Friday and were in danger of a second consecutive road loss. Five minutes later, Ciara Duffy's 3-pointer gave South Dakota a lead it wouldn't relinquish.

Allison Arens scored nine points in the run that secured the lead, and her 12 fourth-quarter points are more than she has scored in most of South Dakota's games this season. But Arens is also someone who scored 20-plus points on 14 occasions as a sophomore. For all of its offensive balance, South Dakota has multiple players who can take over for stretches of games -- including Arens off the dribble and on the perimeter, and Hannah Sjerven inside. (Last ranking: 5)

2. Gonzaga (17-2, 6-1 West Coast)

Rather than try to discern some great truth from Gonzaga's 70-68 loss at BYU last week, let's just note how much we're looking forward to the rematch in Spokane in a month.

Gonzaga gave away an early double-digit lead but had a look at a 3-pointer to win and then a second-chance putback attempt that would have forced overtime. There were plenty of things for the Bulldogs to regret -- like points left on the free throw line or fourth-quarter defense -- but the loss was no damning indictment. Indeed, two days later, Gonzaga coasted to a 25-point win at San Diego, piling up 25 assists on 35 field goals. (Last ranking: 1)

Myah Selland is a name worth remembering. Unless you're a referee, in which case South Dakota State would appreciate you forgetting all about her. With Macy Miller's time in Brookings ending, Selland looks every bit a star -- or a co-star alongside Madison Guebert -- in waiting.

A former top-100 recruit, Selland averaged 15.4 points, 6.1 rebounds and 3.6 assists in a 10-game stretch that concluded with a win against Oral Roberts Jan. 12 and included strong lines against Oregon, Drake and South Dakota. But fouls limited her to only 18 minutes in the only game South Dakota State has played since. She has been called for 29 fouls in her last eight games. (Last ranking: 6)

4. Drake (13-4, 5-0 Missouri Valley)

A curious thing happened when Drake beat Loyola last week. The Bulldogs won despite hitting just four 3-pointers and seven free throws, near season-lows for both. Credit some of that to Loyola's defensive development under third-year coach Kate Achter, but it's also the exception that proves the rule for Drake. Though the 3-point shot is Drake's signature offensive tool, it is balanced by its ability to get to the free throw line. The Bulldogs rank 26th nationally in 3-pointers, but they average more free throws per game than the eight teams immediately ahead of them in those rankings.

Drake's Feb. 1 visit from Missouri State, which has won eight games in a row and is tied with Drake atop the MVC, is among the marquee mid-major games in the next two weeks. (Last ranking: 7)

5. BYU (16-3, 8-0 West Coast))

The Cougars make things interesting. The win against Gonzaga marked the third time in an eight-day stretch in which BYU won despite its opponent taking a shot to make or tie the game in the final seconds. Then again, those three teams are a combined 15-3 in their other WCC games, so it's not as if BYU snuck its way in to debut on this list. For now, Gonzaga's wins against Stanford and Rutgers, and the competitiveness of the game in Provo, keeps the Bulldogs higher on this list, even as they look up to BYU in the WCC standings.

Sara Hamson ranks among the best under-the-radar players out there. A volleyball standout at BYU who missed the past season with a knee injury, and the younger sister of former two-sport standout Jennifer Hamson, she's averaging 11.9 rebounds and 4.2 blocks per 40 minutes. (Last ranking: Not ranked)

Central Michigan's home loss against Miami (Ohio) last week marked its first conference loss in Mount Pleasant in more than three seasons, dating to a loss against Toledo in 2015-16. It wasn't the most likely place to stumble, but that's life in the MAC. For now, chalk it up to a frigid spell from the 3-point line as winter sets in across the Midwest. The Chippewas missed 16 of 21 attempts against Miami, marking the second time this season they made fewer than 30 percent of their attempts (the first was a loss at Tulane).

Now Central Michigan faces difficult tests each of the next two weeks: first at Toledo Jan. 23, and then at home against Buffalo Feb. 2. (Last ranking: 4)

7. UAB (17-2, 5-1 Conference USA)

After an overtime loss against Tennessee in November, a result that made their résumé, the Blazers finally suffered a loss that didn't help, against Louisiana Tech Jan. 10.

Credit point guard Miyah Barnes for making sure there wasn't a hangover. Usually the one to get others involved, with a nearly four-to-one assist-to-turnover ratio, Barnes scored 13 of her season-high 23 points in the second half of a difficult win against Southern Miss two days after the loss against Louisiana Tech. She had topped 13 points in a game just four times.

UAB has a chance to define its conference season against contenders for this list in the next two weeks, playing Rice at home Saturday and Middle Tennessee on the road a week later. (Last ranking: 2)

Opening MAC play with games against Buffalo and Central Michigan in the span of five days was always going to be a challenge, so the home loss to the Chippewas after a road win against the Bulls was a reasonable return. And with the exception of a wild fourth quarter last week in a win against Kent State -- the two teams combined for 57 points in the final 10 minutes -- it has been business as usual since for the Bobcats.

Conference opponents have yet to figure out talented redshirt freshman Erica Johnson. Even with a quiet scoring night in the overtime win at Buffalo, she's averaging 16.4 points in MAC games. That's up from 11.6 points per game out of conference. (Last ranking: 3)

It's always nice to have someone who can throw in 43 points on a given night, as Cierra Dillard did in an overtime win against Eastern Michigan when this ranking period began two weeks ago. But as Buffalo builds toward a brutal close to MAC play, with four of its last seven games against Central Michigan, Ohio or Toledo, it's also worth watching Theresa Onwuka's development as a secondary scorer. Until a rough outing in Buffalo's last game, when the Bulls missed her points in a narrow win, the junior had been averaging 12.2 points per game since Thanksgiving. And despite playing the most minutes of her career, she's still shooting 50.8 percent from the field. (Last ranking: 8)

10. Rice (14-3, 5-0 Conference USA)

Two Conference USA teams were in the running for this spot, with Rice edging fellow league unbeaten Middle Tennessee for now. The two teams play Thursday in Tennessee, their only regular-season meeting, so it won't take long to get feedback on this choice.

Redshirt sophomore Nancy Mulkey makes an already-stingy defense more daunting. In nine games, the 6-foot-9 Oklahoma transfer who sat out the opening weeks with a wrist injury has 29 blocks -- more than the rest of the team combined. And her seven double-digit scoring games have given the Owls a complement alongside Erica Ogwumike. (Last ranking: Not ranked)