SALT LAKE CITY (AP) -- Two years ago, BYU saw its hopes of winning in Salt Lake City dashed by a last-second blocked field goal.
Saturday night, the 25th-ranked Cougars had two late chances only to have the same result, this time a 24-21 loss to their bitter rival.
Utah defensive tackle Star Lotulelei blocked Justin Sorensen's 51-yard attempt with 1 second remaining after the officials put time back on the clock following a third-down incompletion.
The Cougars would get another shot, from 15 yards closer after the frenzied crowd prematurely rushed the field, and Utah was assessed a penalty.
Riley Stephenson's 36-yard attempt with no time left clanked off the left upright, sending the crowd back on the field for good to celebrate the upset.
For a game that was tied 7-7 at halftime, the finish was as wild as they get.
The win gave the Utes (2-1) a new outlook on the season, especially with USC's loss to Stanford and losses by fellow Pac-12 South foes Arizona State and Colorado.
The loss, meanwhile, is sure to knock BYU (2-1) out of the Top 25, and could hurt the Cougars' hopes for something better than a Poinsettia Bowl.
Credit senior quarterback Jon Hays, a stout defense and some special team plays.
Hays passed for two touchdowns in his first start this season in place of Jordan Wynn, who suffered a career-ending shoulder injury in last week's OT loss to Utah State.
He opened the scoring with a 17-yard pass to Westlee Tonga, who tallied his first career TD reception.
His second, a 39-yarder to Dres Anderson, gave Utah a 24-7 lead late in the third quarter. In between, cornerback Moe Lee also returned a fumble 57 yards for another.
But the Cougars refused to quit.
Riley Nelson rallied BYU late, including a 1-yard TD pass to Kaneakua Friel that pulled the Cougars within 24-21.
He finished 17 of 35 for 206 yards, but also was intercepted once and sacked four times.
He knew he was in for a tough one when the first snap on BYU's initial possession scooted low past him. He scooped it up in the back of the end zone and was about to be tackled when Joe Kruger grabbed his face mask, voiding the safety and giving the Cougars a first down at the 20.
BYU punted six plays later and Charles Henderson's 57-yard return set up Hays' 17-yard touchdown pass to tight end Tonga, who made a one-handed grab over linebacker Kyle Van Noy.
Special teams continued to be game-changing, with Utah converting a fake punt on fourth-and-2 from its 24, only to see the drive end when Russell Tialavea blocked Coleman Petersen's 37-yard field goal attempt.
BYU's Sorensen, who had been injured throughout fall camp, was wide left on a 44-yard field goal attempt in the second quarter.
The Cougars finally got on the board with 4:40 left in the half on Nelson's 10-yard touchdown pass to Cody Hoffman, who extended his consecutive game streak with a catch to 22 games.
Hays was composed and tough, and his mobility helped.
He started 7 of 10 for 86 yards and a touchdown as BYU took the early lead, and kept another first-quarter drive alive with a 14-yard pass on third-and-11, and 14-yard pass on third-and-10.
The Utes were without starting free safety Eric Rowe because of a hamstring injury. And while running back John White insisted he would play, he did not play because of an ankle injury.