He fanned five and walked none while allowing just two earned runs in the big victory.
Meanwhile, second baseman Jack Mayfield racked up three hits and an RBI in four plate appearances, also scoring a run.
"I thought our guys fought hard today and I was proud of the effort," said OU head coach Sunny Golloway. "Dillon was just Dillon today. He's a special guy. You don't get freshman All-America honors for nothing and he has backed that up so far this year."
The Sooner offense gave Overton an early cushion in the top of the first inning when Mayfield doubled down the left field line, scoring shortstop Caleb Bushyhead, who led off the game with a walk.
Center fielder Max White then plated Mayfield on a sacrifice fly.
Tech trimmed the lead in half in the bottom of the first, as center fielder Barrett Barnes slammed a solo homer, but catcher Dylan Neal got OU back on the board in the top of the second with an RBI single and extended the lead to 3-1.
The Red Raiders' second run in the bottom of the third again made it a one-run game, but right fielder Cody Reine extended it back to two in the top of the fifth on an RBI fielder's choice.
Tech cut it to 4-3, the third such time in the game where it was a one-run lead for the Sooners, but OU again responded.
"Dylan Neal has done a good job and I was really proud of Brian Brightwell," Golloway said. "We have some freshmen that are really battling out there. There were a lot of positives today."
Brightwell and Neal each finished with a pair of hits and an RBI.
The two teams get back to action in the rubber match at 1 p.m. Sunday.