Call it a Group of Five street fight.

Sean Frazier, Northern Illinois' chatty athletic director, recently slammed the American Athletic Conference (AAC), for portraying itself as a power league along with the ACC, Big Ten, Big 12, Pac-12 and SEC.

Frazier said claims of dominance by the AAC trivialize the efforts of other Group of Five programs in the Sun Belt, Mountain West, Conference USA and MAC.

AAC champion UCF, of course, finished as the only undefeated team in FBS with a 13-0 mark in 2017.

"What it does is marginalize the Mountain West," Frazier said. "It marginalizes our conference. [The AAC] doesn't have the data set to prove that. Most of those schools don't have a history of winning. They don't have a history of winning like Northern Illinois, Boise State."

The Group of Five -- of which NIU's conference (MAC) is a member -- continues to struggle for relevance. The Power Five produce the overwhelming majority of interest, revenue, talent and championships in major-college football.

Former UCF coach Scott Frost said in early January that his team was "insulted" by the College Football Playoff Selection Committee after the Knights finished undefeated and were left out of the top 10 in the final CFP Rankings. UCF AD Danny White hung a national championship banner, and the school staged a championship parade after going undefeated. The Knights, which have taken their national championship claim to further levels, finished No. 12 in the CFP Rankings before defeating Auburn in the Peach Bowl.

"Don't try to bully the committee," Frazier said of UCF. "That's what these guys are doing now. If you want to put a banner up that says 'national championship,' God bless you. You can do that. I've got no problem with [White] doing that. But to say they should have been in the final four is an unrealistic expectation."

Frazier made headlines last year when he advocated for a Group of Five playoff. The former Alabama walk-on and deputy AD at Wisconsin under Barry Alvarez has been at NIU since 2013.

The AAC is generally accepted as the best Group of Five league in the CFP era (since 2014). It has snagged two Group of Five automatic New Year's Six berths in the first four years of the College Football Playoff (Houston in 2015, UCF in 2017).

But the TV marketplace long ago determined the American and the other Group of Five leagues receive only a fraction of the revenue of their Power Five counterparts.

It remains nearly impossible for any of those teams get to the playoff. Nevertheless, the AAC from the beginning has marketed itself as a "Power Six" conference.

AAC commissioner Mike Aresco responded to Frazier's comments, telling CBS Sports that "'Power Six' is no longer a mere narrative. It reflects a reality based on our results and facts that speak for themselves. The fans spoke up for UCF, which proved its case.

"Our focus remains the same: to compete at the highest level of college sports. Our Power Six campaign is about us, not about anyone else."

Frazier is steadfast in his belief.

"So I'm supposed to give them [respect] because they've got some false narrative of P6? No," Frazier said. "I think people know that. That's the reason they don't have a [Power Five designation] now is those teams have not historically been good in football. That's why there is a Big East basketball and American in football. [The market] looked at the football, and they were horrible. That was the difference."

The AAC was formed in 2013 in the latest round of conference realignment. Former basketball-only members of the old Big East broke off and retained the Big East name.

Northern Illinois has a chance to earn the New Year's Six berth in 2018 based on its nonconference schedule strength alone. The Huskies are coming off an 8-5 season into 2018 with what might be the strongest nonconference schedule in the country: at Iowa, Utah, at Florida State and at BYU. NIU is believed to be the only Group of Five program to play four Power Five teams in nonconference. (BYU, an independent, is generally accepted as a Power Five-level opponent.)

Last year, the Huskies became first MAC team to win at Nebraska. In 2012, Northern Illinois grabbed the automatic Group of Five berth in the BCS before losing to Florida State in the Orange Bowl.

"You would have to do something ridiculous just to get into that [playoff] because your [Group of Five] conference schedule would always be ridiculed," Frazier said. "I'm still not there to believe we should be playing for a national title for a number of reasons. The wear and tear of the these conferences [for one]. The SEC West or ACC -- week in, week out -- require that you're tested every weekend. Am I tested every weekend in the MAC? Probably not."

While Frazier admitted that UCF "would have hung with the top four teams" in the playoff, "I totally believe they would have lost," he said.

"I would say UCF was the best G5 school based on who they played," Frazier added. "The way they handled Auburn. The way they handled their league. This year it was definitive.

"In future years, it's going to be tougher."