The Cougars were granted another play with 1 second left, the fans were cleared from the field and kicker Justin Sorensen lined up for a 51-yard field-goal attempt.
The Utes blocked it, and the crowd again stormed the field.
But the play still was live as jubilant fans dashed across the grass with the ball bounding around the field and players chasing it.
Referees called a 15-yard penalty for the fans entering the field during a live play. They ordered the fans to the sidelines again, stunningly giving Stephenson a different kicker this time another chance to send the game into overtime.
That's when the game finally ended, with the ball clanging off the left upright many fans will recall the famous "doink" game in 1998 and the fans finally got to celebrate a third straight Utah victory in the long-running series that won't return to Rice-Eccles Stadium until 2016.
Throughout most of the fourth quarter, it appeared the Utes' 17-point third quarter would settle things.
Cornerback Ryan Lacy intercepted a pass that led to a field goal, safety Moe Lee returned a fumble 47 yards for a touchdown and quarterback Jon Hays hit receiver Dres Anderson with a 39-yard touchdown strike in the quarter, which ended with the Utes ahead 24-7.
But the Cougars drove 75 yards for a Jamaal Williams touchdown run early in the fourth quarter to make it 24-14.
They scored again on a 1-yard pass to Kaneakua Friel to make it 24-21 with 3 minutes, 39 seconds left four plays after Utah punter Sean Sellwood took a loss deep in his own end rather than risk having his kick blocked by the oncoming defenders.
But that's when things really started getting crazy.
The Utes had the Cougars pinned deep in their own end and seemed to have them stopped with time running out. But receiver Cody Hoffman somehow got loose down the right sideline to haul in a 47-yard pass to the Utah 34-yard line on fourth-and-19.
There were 10 seconds left.
Quarterback Riley Nelson promptly spiked the ball for the Cougars to stop the clock with 8 seconds. But referees improperly restarted the clock before the next play began, igniting all the chaos.
The game was weird even before that.
It was sloppy and marred by 22 penalties, and Nelson had both the best luck and the worst at it.
Nelson fumbled or appeared to fumble six times through the first 2 1/2 quarters, and every time the Cougars either recovered or retained possession because of a penalty or ruling that the fumble actually was an incomplete pass.
But when a snap sailed past Nelson midway through the third quarter on the possession after Petersen had turned Lacy's interception into a 48-yard field goal the Cougars could not fall on it before Lee scooped it up and raced to the end zone for a 17-7 lead.
Nelson finished 17 of 35 for 206 yards, two touchdowns and the interception, while Hays was 18 of 27 for 196 yards and two touchdowns for the Utes, who also played without apparently injured running back John White.