The Sooners forced overtime by milking the clock on a 17-play, 86-yard drive that spanned more than six minutes and left Oklahoma State without any time to respond.
Blake Bell cashed it in on a 4-yard fourth-and-1 run with four ticks to go.
OU then won the coin toss and held Oklahoma State to a 26-yard field goal try that allowed the Sooners to have a chance for the game-winning score.
Still, they might not have had that opportunity without the play of their two transfer wide receivers.
Fresno State transfer wide receiver Jalen Saunders' 81-yard punt return for a touchdown, followed by Penn State wide receiver Justin Brown's ensuing catch from quarterback Landry Jones on the 2-point conversion tied it up at 38 early in the fourth quarter after the Sooners had trailed all game.
The two combined for 25 catches and 308 yards as well as a receiving touchdown by Saunders in the first half.
As indicative by that, they paced the Sooner offense all night and were a huge reason why quarterback Landry Jones went out in his final home game with 500 yards on 46-of-71 passing, including three touchdowns to just one interception.
The Sooners twice trailed by double digits and twice were down 14, first when they fell behind 14-0 off a pair of touchdown runs by Oklahoma State running back Joseph Randle, from one and three yards out, respectively.
That marked just the second time all season OU trailed out of the gates.
OU again trailed by more than 10 when Randle pounded in for his fourth touchdown of the game late in the third quarter, a 7-yard scamper, that made it 38-27.
But a Mike Hunnicutt field goal, plus the two outstanding plays by the newcomers, notched it, setting up the dramatics down the stretch.
OSU quarterback J.W. Walsh made it 45-38 with his 2-yard touchdown run with 10:48 remaining.
The Sooners looked poised to tie it up inside the 8-minute mark, but their quest ended in a turnover on downs.
A rare defensive stop, a three-and-out no less, ensued.
And they wouldn't give it up again until scoring in the waning seconds of regulation when Bell powered in for the tie.
Hunnicutt, who earlier missed a 32-yard try, connected on a 25-yard attempt to get the crimson clad on the board late in the first frame, at which point it was 14-3.
Back came the Cowboys on an 11-play, 44-yard drive that extended the lead again out to 14 with a 42-yard Sharp field goal.
But that's when the Sooners finally started to wake up.
On a third-and-2 play midway through the second quarter, Jones found fullback Trey Millard out of the diamond formation for a 14-yard touchdown to chop the lead in half.
OU proceeded to drive 81 yards on seven plays and Jones found Fresno State transfer Jalen Saunders for the 9-yard tying touchdown toss.
Randle and the Cowboys had a response of their own, though, as he completed a first half hat trick on a 4-yard touchdown scamper, and it was 24-17 with a minute and change left in the first half.
That was all the Sooners needed, however, to tie it up again.
Jones marched his troops down methodically and found wide receiver Kenny Stills for a 15-yard touchdown that required a little fortuitous bounce.
Nonetheless, he hung on and it was squared at 24 heading into intermission.
It didn't take long for OSU to break that tie in the second half, as Chelf found receiver Josh Stewart for a 75-yard touchdown out of the halftime gates.
OU trimmed the lead to 31-27 on its first possession of the second half with Hunnicutt's 45-yard field goal.
The Sooners later had a chance to take the lead, but Millard fumbled in the Belldozer package, and that opened the door for the Cowboys to re-seize a double-digit advantage for the second time.
OU out-gained OSU 618-490 and had 44 first downs to OSU's 23.
It had just a trio of penalties for 15 yards, while OSU racked up six for 55.
But the pair of costly Sooner turnovers allowed the Cowboys to dictate this 107th edition of Bedlam for majority of the contest.
Clay, who had the game-winner, finished with 13 carries for 59 yards and the touch.
Saunders racked up a game-high 162 receiving yards and a touchdown while catching 10 passes, while Brown finished with 15 receptions for 146 yards, and wide receiver Kenny Stills somewhat silently crossed the 100-yard plateau with his 103 and a touchdown on nine grabs.
Chelf was 19-of-37 for 253 yards and a touchdown, but one interception, while Stewart cashed in a touchdown as part of his 11 catches for 150 yards.
Randle rushed for 113 on 21 carries.
The Sooners move into their final game of the regular season when head to Fort Worth, Texas for a showing next Saturday at a time to be determined.
OSU completes the 2012 campaign next Saturday at Baylor also at a time to be set.