Keyone Jenkins hit Grayson Brousseau with a 4-yard touchdown strike to open the second overtime and then passed to Tyren Hornes for a two-point conversion to give UCF a wild 39-31 win over mistake-prone No. 2 BYU on Saturday afternoon in a Big 12 Conference dustup in Orlando, Fla.

The Knights' defense stopped BYU on fourth down on the Cougars' possession in the second OT, with BYU's Bear Bachmeier uncorking three straight incompletions after advancing to the UCF 4-yard line.

Earlier, Bachmeier connected with Legend Glasker for a 28-yard touchdown pass to begin the first overtime but that score was countered by Jenkins's scrambling 25-yard TD hookup with Josh Derry on the Knights' possession in the first extra period.

Jenkins passed for 293 yards and three TDs in the victory, and the Knights (4-3, 2-2 Big 12) beat their highest ranked opponent in program history. Hornes had six catches for 137 yards receiving.

Bachmeier finished with 257 yards and one touchdown through the air, with Kyler Kasper catching six passes for 129 yards for BYU (6-1, 3-1).

Overtime was necessitated when Jenkins was stopped short on a sneak from the BYU 1-yard line with 1:42 to play. The Knights had one more possession in regulation but a 46-yard FG attempt by Will Stone was blocked by Faletau Satuala to end the fourth quarter.

The Cougars started the game with a bang, finding the end zone on a 27-yard TD pass from Bachmeier to Kasper. UCF answered with a 2-yard scoring run by Chambers with 13:44 left in the second quarter.

The Knights jumped to the front via Stone's 20-yard field goal on their ensuing possession. Bachmeier's 1-yard touchdown burst with 3:47 left before halftime pushed BYU back to the lead at 14-10.

That was plenty of time for the Knights. UCF took over at their own 22 with 1:22 to play in the half and drove to Jenkins' 6-yard TD pass to Chambers with four seconds remaining to give the Knights a 17-14 lead at the break.

BYU retook the lead on Sione Moa's 1-yard touchdown plunge on its opening possession of the second half. Jenkins swung back, scoring on a 1-yard TD run with 3:06 to play in the third quarter.

The Cougars' Matthias Dunn then tied the game at 24 with a 47-yard FG with 12:09 to play in regulation, setting the stage for the furious finish.

BYU star running back LJ Martin missed his third straight game due to a lower-leg injury.