The top-seeded Anteaters (22-10, 13-3) play eighth-seeded UC Riverside (10-20, 5-11) in the 6 p.m. game.
UCI's 22 wins are three shy of the school record of 25 set by the 2000-01 team.
The winner of the three-day Big West tournament receives an automatic bid to next week's NCAA Tournament.
"Everyone restarts now at the same point," UCI Coach Russell Turner, the Big West coach of the year, said Monday on a conference call.
Big West play begins Thursday at noon with No. 2 UC Santa Barbara (21-8, 12-4) playing No. 7 Cal Poly (10-19, 6-10), followed by No. 3 Long Beach State (14-16, 10-6) against No. 6 Cal State Fullerton (11-19, 6-10).
The conference on Monday named its all-conference team, led by Big West player of the year Alan Williams of UC Santa Barbara.
He was joined by guard Mike Caffey (Long Beach), forwards Isaac Fotu and Christian Standhardinger (Hawaii), forward Stephen Maxwell (Cal State Northridge) and guard Chris McNealy (Irvine).
Irvine's Luke Nelson was named Freshman of the Year; Fullerton's Michael Williams, a transfer from USF, was named Newcomer of the Year.