It's clear he thinks his spunky team can play with anyone.
"I just know that these kids have the most unbelievable heart," Petersen said.
Petersen and his staff are known for their gadget plays, and they stunned the Horned Frogs with one called "Riddler" - a gutsy fake punt with game tied 10-10 in the fourth quarter and the Broncos facing fourth-and-9 on their own 33-yard line.
Punter Kyle Brotzman hit wide-open Kyle Efaw with a 30-yard strike, and four plays later, Doug Martin scored the decisive touchdown on a 2-yard run.
For the second time in four years, the Broncos (14-0) won the Fiesta Bowl with a YouTube-worthy play.
"I think that's what they expect us out of us, so we're happy to deliver," Petersen said.
TCU coach Gary Patterson said the Horned Frogs (12-1) had worked on the fake in practice, but they were caught flat-footed.
"The fake punt was a great call," Patterson said. "They outcoached us on that play."
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The trickery evoked memories of Boise State's BCS debut three years ago, when it pulled out a passel of gadget plays to defeat Oklahoma on the same field.
"Our coaches are creative and they dial stuff up and it works a lot of the time," said Efaw, whose team became the second in modern history to go 14-0, joining Ohio State in 2002.
Unlike the thriller against OU, this game offered little drama for the first three quarters.
It was the first time two schools from conferences without automatic BCS bids have met in one of college football's biggest bowls. But for long stretches TCU and Boise State played as if they belonged in the Poinsettia Bowl, the site of TCU's 17-16 victory over Boise State in December 2008.
Boise State entered as the nation's highest-scoring team (44.2 points), and the Horned Frogs were fourth (40.7), but their expected offensive duel turned into a tedious series of punts.
Neither team could muster an offensive touchdown until the final minute of the first half, when TCU's Andy Dalton hit Curtis Clay for a 30-yard score to make it 10-7. TCU's Ross Evans kicked a 29-yard field goal to tie it at 10 heading into the fourth quarter.
The game appeared to be dragging toward overtime until Petersen's gutsy call. After taking the lead, the Broncos called on their unheralded defense to lock up the win.
TCU took over at its own 1 with 1:06 remaining and marched to the Boise State 30 before cornerback Brandyn Thompson disrupted a pass by Dalton, and Winston Venable picked it off with 18 seconds remaining.
Thompson had two interceptions. He returned the first 51 yards for the game's first score, and his second one set up the Broncos' winning drive.
Dalton had thrown only five interceptions in 279 pass attempts during the regular season, when he earned first-team All-Mountain West Conference honors.
Dalton finished with 272 yards and a score through the air, but was intercepted three times.
The Broncos are one of only three remaining unbeatens, along with Texas and Alabama, who will play for the BCS national title on Thursday night.
Some wondered whether the Broncos deserved a shot at the championship. On this night, they were just barely good enough to snap the Horned Frogs' 14-game win streak.
Asked if he thought Boise State should be No. 1, Efaw replied, "Probably not. But I mean, maybe next year. I don't know. We have a great team and we fight hard and we're undefeated."