SAN DIEGO - The Boise State football team wanted perfection.

The TCU defense demanded it.

And because the No. 9 Broncos were a smidge off all night, the No. 11 Horned Frogs edged them 17-16 on Tuesday night at Qualcomm Stadium in a Poinsettia Bowl thriller - spoiling the Broncos' undefeated season.

The Broncos settled for field-goal tries on four of their five scoring opportunities - including a potential go-ahead drive in the fourth quarter, while facing their first second-half deficit of the season.

"We had a couple times if there was a few more inches we had a biggie," sophomore wide receiver Austin Pettis said. "It's a completely different ballgame - and that's just the way it goes sometimes. We fought hard. We made the plays. We just didn't make enough of them."

The Broncos squandered a 13-0 first-half lead and freshman quarterback Kellen Moore tossed an interception on their first play when they got the ball back with a chance to win the game in the final 2 minutes.

The Broncos (12-1) lost their bowl game for the fourth time in five years. All of those games were decided in the final 2 minutes.

"We almost did it, went undefeated, but we slipped at the end," sophomore safety Jeron Johnson said. "It's motivation, that's what it is. We feel that we have one of the best defenses in the country and we didn't show it today."

The disappointment will be felt across the locker room.

For the offense, which produced just 250 yards, put the defense in a bind and wasted a first-and-10 at the TCU 14-yard line in the fourth quarter.

For the defense, which had carried this team all season but allowed the Horned Frogs (11-2) to hold the ball for more than 36 minutes and rush for 275 yards.

And for kicker Kyle Brotzman, who nailed three field goals but missed a critical 38-yarder.

Petersen, always the offensive coach, put the blame squarely on the Broncos' red-zone performance. They knew they needed to capitalize on the few opportunities they would get against the nation's No. 2 defense, and couldn't.

"That's what got us - too many field goals," Petersen said. " I knew a couple of those field goals were going to come back to haunt us."

None more than the last one.

TCU scored on a 17-yard run by Joseph Turner for a 17-13 lead with 8 minutes, 51 seconds left in the game - the first time the Horned Frogs led in the game and the first time the Broncos hadn't led in a second half all season.

The Broncos responded with some of their best-looking plays of the night - and in a gut-wrenching series of events, couldn't get into the end zone with any of them.

On the second play of the drive, Pettis broke wide open. He probably would have scored but Moore's throw was too high and Pettis had to make a spectacular leaping catch as he fell to the ground.

On the fourth play, Moore hit wideout Vinny Perretta with a swing pass. Perretta eluded a defender and was headed for the end zone when he stepped on the sideline - settling for a 13-yard gain.

On the fifth play, tailback Ian Johnson broke free down the right sideline and dove for the pylon. He went out of bounds at the 1-yard line, but the play was called back on a holding penalty on guard Jon Gott.

And on the seventh play, wide receiver Jeremy Childs was about to come open for an easy touchdown when safety Steven Coleman grabbed him for a wise - and touchdown-saving - pass-interference penalty.

Those were four chances to take the lead - and none quite worked out. The Broncos settled for a field goal that made it 17-16 with 4:47 left.

"When you get in the end zone against these guys, you're excited," Petersen said. "To see a yellow hanky hanging out there to bring it back was very disappointing, because you've got to earn it against TCU. We had our chances. We just didn't capitalize."

Said Perretta: "I'm not going to say we should have beaten them or this or that, but we had our opportunities. We just didn't take advantage of them - and most of that is because they're a great defense."

The Broncos got one more legitimate chance, too. The defense, which nearly provided a huge play when cornerback Brandyn Thompson dropped an interception near midfield, gave the Broncos the ball at their own 17-yard line with 1:53 to play and one timeout.

It was plenty of time. And all BSU needed was one of those field-goal attempts.

But on the first play, Moore's pass sailed behind wide receiver Julian Hawkins and TCU senior safety Stephen Hodge grabbed his first interception. Moore said he was expecting Hawkins to run his route a little deeper, leading to the inaccurate throw.

"You can look back and have about 40 plays that probably were what-ifs," Moore said. "At the end of the day, we didn't get them."

The Broncos built a 13-0 lead in the first half.

A tricky kickoff return (Perretta threw a lateral to Ian Johnson) set up a field goal and Johnson provided a 20-yard touchdown run, which gave him sole possession of the WAC record with 58 career rushing touchdowns and the Broncos a 10-0 lead in the first quarter.

Freshman defensive end Byron Hout sparked the Broncos in the second quarter - picking off a screen pass and rumbling 62 yards to the TCU 11-yard line. The Broncos lost yards on two straight plays and settled for a field goal, a sign of what was to come.

"I was really hoping (Hout) was going to get in there on his own," Petersen said. "We couldn't get it done when we needed to. We get it done one time and not kick one of those field goals, it's a little bit different."