Mike Bercovici collapsed on the Coliseum turf after he released his final throw for Arizona State, cramping up from dehydration.
Jaelen Strong wasn't sure he could get to it, but he sprinted and leaped -- and wasn't quite sure how he ended up with the ball in the end zone, his teammates mobbing him.
When Bercovici and Strong finally got up, the Sun Devils celebrated an improbable comeback capped by an unbelievable finish.
"You never know what this game can come down to," Strong said.
Strong caught a 46-yard touchdown pass from Bercovici as time expired, and Arizona State scored three TDs in the final 3:53 to shock No. 16 Southern California 38-34 on Saturday night.
Bercovici capped his 510-yard, five-touchdown passing performance with his third scoring pass to Strong, who slipped in front of USC's Hayes Pullard at the goal line and pulled in the Hail Mary, walking into the end zone stunningly untouched.
"I'll be honest, it was a little bit of a prayer," said Bercovici, the San Fernando Valley product making his second start in front of dozens of friends and family.
"I just immediately fell to the floor. I saw Jaelen take a step in the end zone, and I don't think I could have made it down 50 yards to the end zone. It was an indescribable feeling. I've got people telling me, `Get up, get up, get up!' But all I wanted to do was run upstairs to my mom and give her a big hug."
A week after giving up 62 points in a humbling loss to UCLA, the Sun Devils (4-1, 2-1 Pac-12) stormed the field to celebrate their first win at the Coliseum since 1999.
"That was the most unbelievable night I've ever had in coaching," Arizona State's Todd Graham said. "When he caught that ball, my heart stopped. You can be where we were last week, and be here this week."
Arizona State burned its three timeouts in the third quarter, but got the ball back at its 28 with 23 seconds left. Bercovici hit Gary Chambers for 26 yards before launching his final throw into a thicket of USC defenders.
"I saw the ball in the air, and the first thing I thought was, `I'm going to get this,"' said Strong, who had 10 catches for 202 yards. "I didn't know if I could get to it, but I just put my head down and kept running. I was laying in the end zone, and I don't even remember (catching) it. I blacked out."
Bercovici followed up his record-setting, 488-yard passing performance against UCLA with an even bigger night, also hitting Strong for a 77-yard TD midway through the second quarter while filling in for injured Taylor Kelly.
Cody Kessler passed for 273 yards for the Trojans (3-2, 2-1), who led 34-25 with 3 minutes to play. USC recovered two onside kicks and got a 53-yard TD run by Buck Allen in the final minutes, but the Trojans' pass defense -- which hadn't allowed a touchdown pass all season -- repeatedly came unglued.
"You learn the hard way in games like this," USC coach Steve Sarkisian said. "It was an awkward Hail Mary. The ball floated back to the middle of the field. It was a heck of a play by (Strong) tracking it."
Arizona State has won three of the schools' last four meetings, including a 62-41 victory in Tempe last season that led to USC coach Lane Kiffin's firing a few hours later. Sarkisian's first loss to the Sun Devils also stings in a totally different way.
USC also changed its defensive call late on the final play, leaving players confused.
"It was great execution by their offense," Pullard said. "(Strong) went up there and got the ball and got the job done."
Kessler scrambled for an 8-yard TD in the fourth quarter, and Allen rushed for 143 yards and two TDs for the Trojans, who appeared to be on the way to an impressive win. USC's defense held the Pac-12's best rushing offense to 31 yards, a whopping 231 below its average.
Arizona State couldn't get rolling on offense until just 6:26 remained. Bercovici hit D.J. Foster with a 21-yard touchdown pass, capping the 98-yard march.
Randall Telfer recovered the onside kick before Allen broke straight up the middle for his second scoring run. But Bercovici hit Cameron Smith for a 73-yard score moments later when cornerback Kevon Seymour misplayed the receiver.
Pullard recovered another onside kick, but USC couldn't move the ball. A poor punt by Kessler -- who was kicking because USC's long snapper is injured -- gave decent field position to the Sun Devils.
With the game-time temperature at 93 degrees during California's October heat wave, Nelson Agholor injected excitement into the first quarter with a 53-yard TD punt return.
USC was in command after a 79-yard scoring drive to open the fourth. Kessler avoided a sack and scrambled 8 yards through the heart of the defense, taking hits and stretching over the goal line.