First baseman Evan Mistich beat out a very close play at first for an infield single in the bottom of the ninth, plating left fielder Erik Ross to propel them to the bracket finals set for Saturday morning at Chickasaw Bricktown Ballpark.
"I was just trying to get down the line as fast as I could, beat the throw, score that run, of course," Mistich said. "I was pretty confident [I was safe]."
But the Sooners wouldn't have been in the position they were in had it not been for a huge seventh inning homer off the bat of right fielder Cody Reine.
Reine, who battled back from an 0-2 count and looked like he might have been hit by a pitch, smashed a 2-2, belt-high fastball over the Baylor bullpen behind the right field wall to tie the game at two apiece.
"The guy had some good stuff," Reine said. "His breaking ball was sharp. He just kept pounding it in on me, you know, so I mean, I thought it grazed me. Just trying to pass it off to Max [White] because I have high confidence in Max that he would get the job done if I'm on first base. But the umpire didn't see it that way and we got to swing the bat one more time.
"Selfishly yeah, I'm glad I got to swing it again but for the team effort, you know, I would have been happy either way if I got on first base because I have a feeling Max could lose a ball at any second."
Before that, Baylor had led all the way since the fourth when it scored a pair of runs off Sooner starter Jordan John.
The threat, which started with a one-out walk and single off John by designated hitter Josh Ludy, culminated in a pair of runs for the Bears.
First baseman Max Muncy and third baseman Cal Towey each recorded RBI singles to help Baylor lead out to a 2-0 lead in the inning.
"Baylor's hitters squared the ball up pretty good," said John, who was pelted with several shots back to the mound in the contest. "I made a play on two of them and then the third one kind of got away from me. That's why we do PFP's, you've got to be ready and have a quick reaction time. I was able to make a couple of plays, and help keep our team in a position to win the game today."
Those came in the second and fifth, when Baylor stranded a runner each.
They enabled OU to cut into the deficit in the fourth.
Second baseman Jack Mayfield led off with a double into the left field corner and eventually scored and cut the lead in half when the Bears traded a double play ball for a run.
Meanwhile, John settled down and ended up getting off the hook with a no-decision and closer Steven Okert came in and slammed shut Baylor's offense, allowing just one baserunner on a walk in the eighth and ninth innings en route to earning the victory.
"We knew once Cody hit the bomb, we were going to go to Okert," said OU head coach Sunny Golloway. "We've got two other guys getting loose and a quality bullpen, but Okert is the leader out of that bullpen. You don't want to burn Okert if you're down 2-1, I don't think that would be wise.
"Once Cody hit the home run, it was very apparent that it was going to be Okert's game."
Just as Okert was brilliant out of the pen, the Sooners shook off some shaky defense early in the game to come up with some key plays down the stretch.
One was a questionable 1-3-6 put out when Okert picked off a Baylor base runner that appeared to be safe.
Another was a great diving play by Sooner shortstop Caleb Bushyhead, who leaped up and fired to first to retire a runner cruising down the line.
"I thought the middle infield play was absolutely terrific," Golloway said.
All of that contributed to a huge victory that means Baylor or Kansas State must beat OU twice to earn a trip to Sunday's championship game.
And the Sooners feel good about that, as they are a combined 6-1 against those two teams this year, with four straight victories over the Bears.
"I believe in matchups," Golloway said. "We just match up really well with them. I know we've come out on the top side four straight. Until we got the pitching worked out, our numbers weren't good but we knew the talent of our arms and it was just a matter of getting them lined up and putting the pieces of the puzzle together."
Any victory for the Sooners will pit them against the winner on the other side of the bracket.