SAN DIEGO_San Diego State couldn't have picked a worse time to play its worst game.
SDSU rose to No. 19 in the national rankings this season while finding ways to win its first six games, even when mistakes were made or the Aztecs were outplayed.
That wasn't nearly the case Saturday night at SDCCU Stadium. The largest crowd of the season _ 49,053 _ watched Aztecs mistakes coupled with a strong Boise State defense lead the Broncos to a 31-14 win in the Mountain West game.
SDSU (6-1, 2-1 MW) never recovered after allowing a punt return for one touchdown and a turnover for another to Boise State (4-2, 2-0) in the first quarter.
The crowd was buoyed briefly by an 89-yard touchdown pass from SDSU quarterback Christian Chapman to wide receiver Fred Trevillion. That provided the Aztecs with their first points, cutting Boise State's lead to 21-7 with 4:15 remaining in the third quarter. It was the fourth-longest pass play in school history and provided SDSU with its first TD of the season by a wide receiver.
It was that kind of big play _ mostly provided by the running game, defense or special teams _ SDSU fans had come to expect this season.
The Aztecs came into the contest as one of the nation's 13 undefeated teams. The loss not only dropped them from those ranks _ and hindered hopes for the Group of Five's access bowl bid _ but dropped them out of first place in the conference's West Division. Fresno State (4-2, 3-0 MW) remained unbeaten in conference play with a 38-0 win over New Mexico. The Bulldogs are next up on SDSU's schedule, coming to San Diego in six days.
Much of the success SDSU had enjoyed while winning 27 of its past 30 games over three seasons was provided by special teams that truly were special, an offense that protected the ball and controlled the clock and an opportunistic defense that produced the nation's biggest turnover margin.
All that went AWOL in the first half against the Broncos, whose defense bottled up running back Rashaad Penny much of the evening while keeping Chapman on the run all night.
SDSU punted away six of its seven first-half possessions. The seventh ended with a Boise State player holding up the ball in the end zone.
The Aztecs also had missed tackles that turned short gains into long ones. There was one 15-yard penalty for running into the punt returner on a fair catch. There was another 15-yarder for a face mask.
Even Penny couldn't get going.
He recorded the 25th 1,000-yard season in school history on a 21-yard carry in the first quarter. Penny's other 11 carries in the first half totaled 1 yard.
Penny rushed for 1,018 yards last season, making him the sixth back in school history with multiple 1,000-yard seasons.
The senior from Norwalk carried 21 times for 53 yards against Boise State, ending his six-game streak of 100-yard games.
A first quarter filled with punts _ six in all, four by SDSU's Brandon Heicklen _ was interrupted when Boise State's Avery Williams returned a Heicklen kick for a 53-yard touchdown and a 7-0 Broncos lead with 6:17 remaining in the opening period.
When SDSU's next drive stalled, Chapman (12-for-27, 240 yards, TD) tried to avoid a third-down sack while in the clutches of a Boise State lineman and hurled the ball toward SDSU running back Juwan Washington. The ball bounced at Washington's feet and was scooped up by Boise State safety Kekaula Kaniho, who raced 34 yards for a touchdown with 4:20 still remaining in the first quarter.
The play was called a fumble for the ball being thrown backwards _ barely _ and the ruling on the field was upheld on review. Boise State had a 14-0 lead, all of it with the Broncos offense watching from the sidelines.
Boise State made it 21-0 three minutes before the half when quarterback Brett Rypien completed a 77-yard drive with a 3-yard touchdown pass to Jake Roh.
After Chapman connected with Trevillion to cut Boise State's lead to 14 points, the Broncos drove right back down the field. They were 2 yards from the end zone when the third quarter ended. The SDSU defense held them to a field goal that made it 24-7 as the fourth quarter began.
SDSU closed it to 24-14 with slightly more than 10 minutes remaining when Penny scored around left end on an 11-yard run. But Boise came right back with a 4-yard touchdown run by Alex Mattison (22 carries, 124 yards, TD) to complete the scoring.
Among the concerns for the Aztecs coming into the game was how to defense Boise State's quarterback(s).
Rypien, the classic drop-back passer, was an all-conference selection the past two years. Senior transfer Montell Cozart emerged this season when Rypien was injured and brought a running threat behind center.
Rypien (11-for-19, 72 yards, 1 TD) took most of the snaps against the Aztecs. Cozart (3-for-4, 53 yards) passed more than he ran, but his presence seemed to created some uncertainty.
