SAN DIEGO -- Boise State stopped Rashaad Penny and ended San Diego State's unbeaten start.
The No. 19 Aztecs (6-1, 2-1 Mountain West) and Penny failed to establish the run or offensive rhythm during a 31-14 loss to the Broncos on Saturday night.
"When you run the ball for 100 yards every game, and you get held to that, that's got to be frustrating," said Boise State linebacker Leighton Vander Esch.
The Broncos defense, which has not allowed an opposing player to rush for more than 100 yards this season, limited Penny to 53 yards and a touchdown on 21 carries.
"The offensive line was terrible," SDSU coach Rocky Long said. "Our running backs can't do what they need to do."
Avery Williams returned a punt 53 yards for Boise State's first touchdown, and less than two minutes later, Kekaula Kaniho returned a fumble by SDSU quarterback Christian Chapman 34 yards for a 14-0 lead in the first quarter.
"I thought all three phases showed up," said Boise State coach Bryan Harsin.
It was the start of an overwhelming performance for Boise State (4-2, 2-0) on defense. The Broncos had 12 tackles for a loss, including four sacks, and San Diego State didn't cross the 50-yard line until the middle of the second quarter.
"At the point of attack, we played physical, and it showed up throughout the entire defense," Harsin said.
Brett Rypien threw a 3-yard touchdown pass to tight end Jake Roh to put the Broncos up 21-0 in the second quarter. Rypien completed 11 of 19 passes for 72 yards.
SDSU chipped away when Chapman hit Fred Trevillion on an 89-yard touchdown pass in the third quarter.
"The long pass probably should have sparked us a little bit," Long said.
Penny added an 11-yard score, his 13th of the season, in the fourth.
Broncos running back Alexander Mattison padded the lead with a 4-yard TD run with 4:52 left. Mattison finished with 128 yards on 23 carries.
"It was a well-rounded loss," Long said.
Boise State: The Broncos won their first game over a ranked opponent as an unranked team since September 2008.
San Diego State: Penny turned his second attempt of the game into a 21-yard gain, making him the sixth Aztec player to have multiple 1,000-yard rushing seasons. He didn't do much else, and as he goes, so go the Aztecs.
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