With the win, the Sooners (49-4) advance to the Regional final on Sunday and await the winner of Saturday night's elimination game between Arkansas (35-19) and the winner of Saturday afternoon's contest between Fordham and Marist.
"It was a hard-fought game by us, and it was quite a clutch performance by us as well," Oklahoma head coach Patty Gasso said. "These athletes gave their all. They know the importance of this game and what it does for you tomorrow. We can stay here all day and have to play again or go home and get off our feet and rest, then come back tomorrow and play one.
"We have the safety net, but we don't want it or need it. We want to get it done. We put ourselves in a nice position moving forward, but everybody fought today. It was a tough battle. We give credit to Arkansas who came ready to play; we were attacking at the plate and ready to make good plays, but they were ready just as well. It was a good battle between two good teams."
The Sooners led 6-1 after five innings of play Saturday, but Arkansas rallied with two outs to put up a four-spot in the sixth.
Andrea Sullivan hit a two-run, pinch-hit home run for Arkansas and Clarisa Navarro added a two-run single later in the frame, chasing OU starter Keilani Ricketts.
Senior pitcher Michelle Gascoigne came on in relief of Ricketts, who finished the day with a line of 5.2 innings pitched, eight hits allowed, five runs allowed, two walks and four strikeouts. With two on and the go-ahead run on second base, Gascoigne struck out Chloe Oprzedek on just three pitches.
"It was definitely huge when Michelle [Gascoigne] got that strikeout," Ricketts said. "Our team really fed off that and it brought us momentum to get those next runs."
The rally thwarted, Oklahoma responded by getting back all four runs with two outs in the bottom of the frame.
Junior Javen Henson, who entered the game as a defensive replacement in the top of the inning, pulled a single through the left side with two away. Junior Destinee Martinez kept things going with a single of her own before sophomore Callie Parsons doubled to left center to score Henson. Senior Brianna Turang walked to fill the bases for Chamberlain.
Working her way into a hitter's count at 2-1, Chamberlain smashed a double over the head of center fielder Stephanie Canfield to clear the bases and put OU ahead 10-5. It marked the second straight game for Chamberlain with five runs batted in.
"That's been our namesake throughout the season, just finding ways to keep the rally alive," Gasso said. "In the end with two outs, Javen (Henson) came up off the bench big time for us, and then our seven, eight and nine kept doing their job whether it's base on balls or base-hits. They found ways to get on. Then Lauren was back on the plate and brought the game up again, so it was just a tag-team effort throughout."
Arkansas looked like it was going to start another threat in the seventh, putting the first two runners on base. However, second baseman Georgia Casey fielded a grounder from Sierra Bronkey, tagged Canfield and then flipped to Chamberlain to turn the double play. Sophomore Shelby Pendley then caught a line drive at third base to end the game.
In the bottom of the first, the Sooners took advantage of a Razorbacks' error to take a 2-0 lead.
Chamberlain led off with a pop-up to first base that Devon Wallace appeared to be camped under. However, Bronkey, playing second base, interfered with Wallace to allow Chamberlain to reach second safely.
A sacrifice bunt from sophomore Georgia Casey moved Chamberlain to third, while Pendley was hit by a pitch to put runners on the corners. Ricketts then fought through an 11-pitch at-bat, including five foul balls with two strikes, before muscling a pitch into shallow center field to score Chamberlain.
With the run, Chamberlain set the school and Big 12 record with her 72nd of the season.
Two batters later, with runners on first and second, junior Brittany Williams lifted a single to the gap in left center field to plate Pendley and stake the Sooners to a 2-0 lead.
Williams padded the Sooners' lead in the third inning when she hit a two-out, solo home run to the bleachers in right center field. It was her seventh of the season and 25th of her career.
Arkansas got a run back in the fourth when Amanda Geile hit a solo home run to center field, but Oklahoma got it back in the bottom of the frame on a bases-loaded walk by Ricketts to make it 4-1.
The lead grew to 6-1 in the fifth inning when Chamberlain pulled a single through the left side with the bases loaded. It was her second straight game in the Regional with five runs batted in.