For the past four years, Notre Dame has taunted the Power 5 with its potential to elbow out a second conference champion from the College Football Playoff, only to lose at least once by mid-October every season.

Following Saturday's resounding 45-23 win at No. 24 Virginia Tech, the undefeated Fighting Irish are in a position to flip the script and exceed expectations in the second half of their season. Notre Dame's 22-point win was its largest road win against an AP-ranked team since 1966, against No. 10 USC. The trip to Blacksburg, which came on the heels of an important home win over Stanford, legitimized Notre Dame's playoff hopes and illustrated the kind of discipline and consistency needed to finish undefeated.

"It's an extremely confident group," Irish coach Brian Kelly told reporters after the game. "We didn't travel some really good players down and we still played really good football. It's a deep team, it's a talented team. But I would say, more importantly, that it's a very confident football team."

The 6-0 record proves it.

Notre Dame has earned three wins over ranked opponents -- Michigan, Stanford and now the Hokies -- putting arguably the toughest stretch of their season behind them. ESPN's Football Power Index projects the Irish will win each of their remaining games, including the most difficult -- the regular-season finale at USC (66.6 percent).

"The mental development of the group is where we're different," Kelly said. "Last year, we could tell you why you win. [This year,] they can tell you how to win. There's a big difference between how you win and why you win. ... They know how to win because there's an attention to detail, and you can't be sloppy. You've got to be smart. It's just a different group, a much more mature group."

An undefeated Notre Dame team is in.

Which begs the question: Who's out?

The trickle-down effect of Notre Dame's independence on CFP contenders is another example why fans either love or loathe the Irish, but they have yet to experience the full impact. With Notre Dame squarely in the playoff conversation, the outlook for the top four each week should be measured against the possibility of the Irish in the semifinals as long as they continue to win.

Considering the Week 6 results, Selection Day could be very easy for the 13-member committee -- and very unfortunate for the Big 12 and Pac-12.

Oklahoma's loss to Texas wasn't eliminating, but it was devastating to the entire conference, dropping the Sooners' playoff chances to just 14 percent, according to ESPN's Playoff Predictor. Even if OU runs the table and wins the Big 12, would the selection committee really rank it ahead of Notre Dame? Probably not, considering what the Sooners' defense looked like Saturday. The loss also left West Virginia as the league's only remaining undefeated team, and while the Mountaineers were able to beat Kansas, they also had four turnovers in the process.

The selection committee goes far beyond the win-loss record, which is why the Pac-12 remains on the bubble, as Washington struggled to beat a winless UCLA team. Stanford, which was simply embarrassed by Utah, suffered its second loss and is out of the picture.

If Washington were to run the table and win the Pac-12, would it earn a top-four spot ahead of Notre Dame? UCLA, which had been outscored 83-31 in the second half through its first four games, inched within a touchdown of the Huskies early in the fourth quarter, trailing 24-17.

Notre Dame, meanwhile, has steadily morphed into one of the best teams in the country over the past three weeks with Ian Book at quarterback. The Irish have established an identity as a true balanced offense, and that was reflected Saturday with 178 rushing yards from Dexter Williams and just 10 incomplete passes from Book (25-of-35 for 271 yards, two touchdowns and an interception).

Notre Dame has been a different team since Ian Book took over three weeks ago. Gregory Fisher/Icon Sportswire/Getty Images

"We've struggled with that during my time here, complementing each side of the ball," Kelly said on Saturday. "We are beginning to do that much better. Our offense is complementing our defense, which we saw today."

Considering the Big 12 and Pac-12 are likely to produce conference champions with at least one loss, Notre Dame -- at least through six games -- looks like a no-brainer for a top-four spot. It's in good company.

Assume No. 1 Alabama wins the SEC, No. 3 Ohio State wins the Big Ten and No. 4 Clemson wins the ACC. There could be a debate whether a one-loss Georgia team, whose only loss would be to Alabama in the conference championship, is simply better than undefeated Notre Dame. Or the committee could consider Georgia and Notre Dame at the expense of Clemson.

Consider this: Notre Dame and Clemson could possibly have two common opponents in Wake Forest and Virginia Tech, if Clemson faces the Hokies in the ACC title game.

That way-too-easy scenario, though, assumes Alabama, Ohio State and Clemson all finish undefeated and Georgia heads into the SEC title game undefeated, too, which is as likely as Nick Saban taking a pay cut.

Thirteen of the past 16 CFP semifinalists have had a loss, the exceptions being 2014 Florida State, 2015 Clemson and 2016 Alabama. While LSU and Oklahoma can still be considered for a top-four finish, they likely can't afford to lose again. One thing we haven't seen happen yet is a two-loss team in the top four.

So goodbye, Auburn, Michigan State, Virginia Tech and Oklahoma State -- all Top 25 teams that suffered their second loss of the season on Saturday.

Where things would get tricky is if Notre Dame stumbles along the way and enters a debate against multiple one-loss Power 5 conference champions. Notre Dame needs Michigan, Stanford and Virginia Tech to finish strong. It also will help if USC is ranked by the time they meet.

For now, Notre Dame is in the best position it could hope for -- which means trouble for somebody else.