After OU had the go-ahead run on second in the top of the ninth inning and failed to score, the Bears walked off in the bottom half of the frame.
Second baseman and nine-hole hitter Steve DalPorto led off with a double, was advanced to third on a sacrifice bunt and after an intentional walk, Baylor's magic and the Sooners' demise took place.
Catcher Josh Ludy ripped an 0-1 pitch into left field off OU closer Ryan Duke, plating DalPorto for the win and ending the Sooners' regular season on a low note.
In fact, the Sooners have now completed the regular season slate without a road series victory.
Baylor did its part early to ensure that, as it scored a pair of runs in the bottom of the second.
After a leadoff single by center fielder Logan Vick, left fielder Dan Evatt smashed a two-run homer over the left field fence.
But Sooner pitcher Dillon Overton, on in relief of starter Jordan John, who was chased after only 1 1/3 innings, limited any more damage when he stranded a couple of Baylor base runners in scoring position to keep it 2-0 heading into the third.
That's where it would stand until the sixth when third baseman Garrett Buechele came through for OU.
An inning later, the contest entered a 57-minute rain delay in a 2-2 tie.
"I don't think it had an effect on the game," said OU head coach Sunny Golloway. "I thought our guys played well after the rain delay and they played well. Both teams kept it clean."
A scoreless seventh and scoreless eighth preceded the ninth inning Baylor heroics.
However, the Sooners had a golden opportunity to take the lead in the top of the eighth, with runners at second and third with two outs, but right fielder Chris Ellison flied out to left.
Ogle and Seitzer were each 2-for-4 with a run scored, and Buechele was 1-for-3 with both Sooner RBI's.
Evatt led the Baylor offensive attack, going 1-for-2 with two RBI's, a run scored and a pair of walks.
OU (40-15, 14-11 Big 12) now awaits its seeding in the Big 12 Tournament.
"As big of a win as it was last night, this is a really painful, disappointing and disheartening loss," Golloway said. "The regular season is behind us, we won 40 regular season games, which is big, but next week is a new season."
Currently, the two are tied, with OU holding the advantage by percentage points.