Oregon State (1-1) struck first when Desiree Beltran hit a two-run home run off OU starter Michelle Gascoigne, but Chamberlain responded in the bottom of the first with her second home run of the year, a solo shot to left field that cut the deficit in half.
"She's such a smart hitter," Oklahoma head coach Patty Gasso said of Chamberlain. "I think pitchers get really uncomfortable because I don't know what you can call that she can't hit.
"She's disciplined, smart, calculated, powerful and quick. Everything you would want in an athlete, she's it."
Oklahoma took the lead for good in the second inning when Georgia Casey delivered a clutch two-out, full count single. With runners on first and second, Casey lined a single back up the middle that got under the glove of Oregon State centerfielder Hannah Bouska and rolled to the wall to drive in Brianna Turang and Chamberlain.
After a scoreless third inning, Oklahoma broke the game wide open in the fourth thanks to the bottom of the lineup.
"We had to shake the team up a little bit around the fourth inning because I felt like we weren't competing at the level we're capable of," Gasso explained. "The bottom part of our lineup stepped forward and did their job by putting themselves on base and handing the bat off to Lauren and the rest of that group.
"That's exactly how it should work, and they executed very well."
Sophomore Callie Parsons picked up the first hit of her career and then reached second as she beat out a throw on Jessica Vest's bunt. Turang then laid down a bunt single of her own to load the bases for Chamberlain at the top of the lineup.
Chamberlain walked on five pitches to bring home Parsons, while Casey followed with a fly ball that died right at the fence for a long sac fly. Jessica Shults walked to reload the bases before Keilani Ricketts walked to drive in another run. With the bases still loaded and one out, Shelby Pendley blooped a single to center field to make it 7-2.
After Oregon State recorded an out, Brittany Williams re-entered the game for Parsons and laced a run-scoring single to center field. Freshman Leslie Miller pinch hit and drew a walk to drive in the first run of her career to make it 9-2 in favor of the Sooners.
Erica Sampson hit for Turang and drew yet another bases-loaded walk to make it 10-2 with Chamberlain coming up to bat for the second time in the inning. On an 0-1 pitch, the Trabuco Canyon, Calif., native sent a deep shot over the wall in right field for her second home run of the game and third of the season.
It gives Chamberlain 33 career home runs just two games into her sophomore season and already puts herself in a tie for ninth on OU's all-time home runs list.
After yielding two runs in the first inning, Gascoigne settled down and secured the win. She struck out nine batters and gave up just three hits while walking one. She improves to 1-0 on the year and 33-4 in her career, improving her school-record winning percentage to .892.
"Once Michelle settled in, I thought she threw extremely well," Gasso said. "It was nice to see her rebound after Oregon State scored early."
The win gives Oklahoma a 2-0 start to the season following a 6-0 win over Stanford on Friday morning, which was highlighted by Keilani Ricketts' no-hitter.
"I think it's important for us to get on a good track, especially against two good teams," Gasso said. "When you walk out here to this tournament, you hope you're ready. They showed that they're ready enough to handle their business, but we still have a lot of work to do.
"Starting 2-0 brings confidence, but tomorrow is another very tough day. Today was a good way to springboard into tomorrow."
Oklahoma will take part in a pair of games on Saturday, beginning with a showdown against No. 5 Oregon at 10 a.m. CT. The Sooners then face New Mexico at 12:30 p.m. CT.