Robert Nycz's 20-yard field goal put Arizona State ahead to stay, and linebacker Scott Von Der Ahe returned an interception 31 yards for a touchdown with 48 seconds remaining to seal a 29-21 victory over Brigham Young on Saturday night.
The Sun Devils (3-4) trailed, 21-13, before mounting their comeback and keeping the Cougars (2-3) from winning at Arizona State for the first time since 1965.
Ryan Wood's one-yard touchdown run 1:35 into the fourth quarter brought Arizona State within two at 21-19, but a two-point conversion attempt failed.
BYU was called for a crucial roughing-the-punter penalty at the Sun Devils 30-yard line with 9:13 to play. Arizona State drove to the Cougars 10 before Nycz's field goal with 5:27 remaining put the Sun Devils ahead 22-21.
The Cougars were at their 20-yard line with 59 seconds to play before Von Der Ahe intercepted a first-down pass from Steve Sarkisian and ran untouched along the sidelines for the game-clinching score.
BYU mounted one last drive but was at the Sun Devils' 22-yard line when time ran out.
It was the Cougars' 20th loss in 25 meetings against their former Western Athletic Conference foe.
Sarkisian completed 19 of 30 attempts for 282 yards.