The six runs, four of which scored on two-out hits, helped UCI junior Matt Summers outduel junior right-hander Mason Radeke, who came in with a 7-1 record and a 2.19 earned-run average.
Summers, who improved to 7-2, allowed six hits and one earned run in eight innings. He struck out a career-high 10 and, for the third straight start, did not walk a batter. He lowered his ERA to 2.06.
It was the 12th start of the season for Summers and the 11th time he gave up two or fewer earned runs. The most earned runs he allowed were three in an April 1 home victory over Cal State Northridge.
"Our guy was really good," UCI Coach Mike Gillespie said of Summers. "He was sensational. I'm really proud of him. He has made such strides, it's quantum leaps that he has made and I'm happy for him.
Both teams scored single runs in the fourth inning and UCI took a 2-1 lead on a line drive single by Leyland with one out in the sixth. Drew Hillman and Ronnie Shaeffer also singled in runs with two outs for UCI.
Ramirez was one of eight Anteaters who recorded hits, helping the hosts, ranked No. 17 by the National Collegiate Baseball Writers' Assn., improve to 30-12.
More importantly, UCI moves to 9-4 in the Big West Conference, adding another game of separation ahead of Cal Poly (20-20, 9-7).
Cal State Fullerton (31-13, 12-4) remains in first place.
But there are reasons for concern for the 'Eaters.
Gillespie said junior shortstop D.J. Crumlich, named a finalist Thursday for the Brooks Wallace Award that goes to the best shortstop in the nation, will likely be sidelined indefinitely by a shoulder strain that occurred on an awkward slide in the first inning Friday.