Buechele collected two hits and drove in four runs in four at bats in the win, and both of his hits fueled the No. 7 Sooners to their much-needed 40th win in 54 games and helped improve them to 14-10 in Big 12 play.
The captain's first hit exploded off his bat and over the wall in left for a three-run homer in the fourth inning to score the game's first runs, but OU's pitching could not hold onto that middle-innings 3-0 lead.
Junior pitcher Burch Smith gave up the lead by allowing Baylor to score three runs, highlighted by a two-run homer by third baseman Jake Miller, in the sixth.
Smith was having a solid outing before Baylor tied the game.
He worked his way in and out of jams throughout the game but was pulled in the sixth.
Smith struck out and walked four batters and allowed six hits in 5 1/3 innings. All three runs that scored on him were earned.
Senior pitcher Bobby Shore, who was removed from the weekend starting rotation due to arm injuries, finished the sixth unscathed but couldn't keep the game tied in the seventh.
The Bears plated the momentary go-ahead run on a sacrifice fly in the seventh set up by a leadoff double. The double was the only hit Shore surrendered en route to his third win.
After a scoreless eighth, the Sooners had the heart of their order coming up in the ninth while trailing by a run.
Ahead in the count, Buechele drilled a misplaced pitch down the third base line to score the runner from second to tie the game and put the winning run at third.
Junior shortstop Caleb Bushyhead, who although wasn't named a captain is one of OU's vocal and on-field leaders, drove a fly ball to the warning track to plate the winning run.
Senior closer Ryan Duke stranded the tying run on second in the bottom of the ninth to earn his sixth save.
The victory keeps the Sooners' hopes of hosting a regional bid alive and forces a rubber game at 3 p.m. Saturday.
OU has a good chance of hosting if it wins the series finale and has a good showing at the Big 12 Tournament. So if head coach Sunny Golloway and his team wants to play at L. Dale Mitchell Park again, the final game of the regular season has to be treated and should be viewed as a must-win situation.