Senior shortstop Ben Orloff went two for four with a run batted in, as did junior catcher Francis Larson.
Senior outfielder Eric Deragisch was also two for four and freshmen Ronnie Shaeffer and DJ Crumlich each had an RBI.
UCI capitalized on an error by Maudlin, failing to handle a routine flip from the first baseman to first base, to score two unearned runs to take a 3-2 lead in the third inning.
“I am mindful of the fact that we caught a couple breaks tonight,” Gillespie said. “Five runs are not very many and we got help to get to five. I think it’s a very, very important win.”
The importance was emphasized when reliever Cory Hamilton was pulled after nine pitches — with a 3-2 count on his second hitter — in favor of Pettis with no outs and a man on in the eighth.
“That was a desperation move there,” said Gillespie, who has seen UCI relievers other than Pettis struggle all season.
Pettis needed just four pitches to record three outs. After a ball to finish the second walk credited to Hamilton, a Cal Poly batter was called out for interfering with catcher Francis Larson’s pickoff throw to second base.
Two pitches later, Pettis induced a double-play grounder to short.
Pettis, who earned his sixth save, ended the ninth with a strikeout.
The three-game series resumes today at 1 p.m.
Big West Conference
UC Irvine 5, Cal Poly 2
SCORE BY INNINGS
Mauldin, DeVincenzi (8) and Brayton; Bibona, Hamilton (8), Pettis (8) and Larson. W – Bibona, 4-1. L – Mauldin, 3-2. Sv – Pettis (6). 2B - Orloff (UCI), Cusick (UCI), Crumlich (UCI). HR – Crocker (CP).
BARRY FAULKNER may be reached at (714) 966-4615 or at firstname.lastname@example.org.