Host Vanguard University won the second game, 9-1, after dropping the opener, 5-2, against Westmont in Golden State Athletic Conference play on Saturday.
Taylor McKnight was two for four with four runs batted in to key the Lions (23-13, 15-9) in Game 2.
Bret Collins was three for four with one RBI and Brandon Sandoval was two for four with three runs scored for Vanguard in Game 2.
Clayton Voechting pitched a seven-inning complete game, allowing no earned runs and seven hits to improve to 5-2 for Vanguard, which had only five hits in Game 1.
Westmont is 21-14, 12-13.
Vanguard University won the first game, but had to settle for a split against Golden State Athletic Conference host San Diego Christian on Saturday.
Lions pitcher Rachel Stalford allowed eight hits in a complete-game 7-2 victory to improve to 9-3, as Taylor Wilson, Brittney Boggs and Summer Penner had two hits apiece and Shelby Kurryllo drove in three runs in the opener.
The hosts rallied from a 7-1 deficit to claim the second game, 8-7, despite three hits from Boggs and four RBIs from Kuryllo.
Vanguard is 24-16, 6-6 in conference.
San Diego Christian is 11-9, 7-5.
UC Irvine 4, Hawaii 3
Kat Facey and Sarah Stadfelt won in singles and doubles to help the host Anteaters improve to 5-0 in Big West Conference play on Saturday.
Facey and Stadfelt combined to win, 8-6, at No. 3 doubles to help UCI (12-5) earn the doubles point.