Erik Folk capped the Huskies' final march with a career-long 54-yard field goal as time expired on the first half, and the visiting team leading.
The key play during the 11-play, 63-yard drive was Jake Locker's 25-yard completion to Jordan Polk – on Polk's first snap of the game.
It was the Huskies' longest field goal since 1999 when John Anderson nailed a 56-yarder versus UCLA.
Folk's boot was No. 3 all-time in UW history.
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The Cougars took their first lead, 13-7, on Riley Nelson's 9-yard touchdown strike to Josh Quezada with 12:08 in the first half.
The UW struck right back, marching 80 yards. Locker scored off a delayed quarterback keeper, sneaking inside the left pylon for a 9-yard run at the 8:43 mark.