The Anteaters knocked off Oregon State, the top-seeded team in the 64-team tournament, on the Beavers' home field.
Irvine defeated Oregon State, 4-2, in the decisive game of the Corvallis Regional late Monday night. The Anteaters routed the Beavers, 14-3, earlier in the regional, but Oregon State forced a deciding final game by shutting out Irvine, 4-0, on Sunday.
Next up for the Anteaters is Oklahoma State, which swept through a regional on its home field, defeating Binghamton, 8-0, and Cal State Fullerton, 13-7 and 6-4.
Irvine (38-23) and Oklahoma State (48-16) will open their best-of-three Super Regional on Friday at 6:30 p.m. PDT in Stillwater, Okla.
Pepperdine (42-16), the only other Southland team still alive, opens a Super Regional series against Texas Christian (45-15) on Saturday at 1 p.m. PDT in Fort Worth.
"Coaches ask two things of their teams — to give the full max of what they have and to do the things we train and practice so much for," Irvine Coach Mike Gillespie told reporters after Irvine's regional-clinching win. "If we were asked if we did those things, I'd have to say we did."
The Anteaters used two starters on short rest to shut down the Pac-12 Conference champion Beavers. Andrew Morales, pitching on two days of rest after starting Irvine's regional opener Friday, pitched 41/3 innings and limited Oregon State to three hits and one run.
The save went to left-hander Elliot Surrey, making his first relief appearance this season after pitching seven strong innings against Oregon State on Saturday. Surrey gave up a hit and a walk in the ninth inning, but then induced a game-ending double play.
Pepperdine advanced by defeating Arizona State, 3-2, and Big West Conference champion Cal Poly, 2-1 and 10-6, on the Mustangs' home field. The Waves will be facing one of college baseball's best pitching staffs in Texas Christian. The Horned Frogs have given up one run or less in 32 of 60 games.