Senior second baseman Tommy Reyes was three for five with one RBI, as seven players contributed to the 14-hit attack.
UCI improved to 17-9, 3-0 in conference to claim sole possession of first place in the Big West. UCI also received the No. 29 ranking by Collegiate Baseball in the poll announced Monday.
Pacific fell to 8-19, 0-3.
UC Irvine 7, Pacific 4
IRVINE — Freshman Taylor Sparks, who belted a walk-off, two-run homer in Friday's series opener, singled in the tying and winning runs in a sixth-run eighth to propel the host Anteaters in the Big West Conference game Saturday.
Senior shortstop D.J. Crumlich was two for five with two runs batted in, while senior first baseman Jordan Fox and junior left fielder Scott Gottschling both had two hits and one RBI for the winners.
Mitch Merten threw three scoreless innings of relief to earn his first collegiate win. He allowed one hit, walked one and struck out one.
Race Parmenter worked a scoreless ninth for his team-leading third save.
UCLA def. UC Irvine
IRVINE — The No. 3-ranked Bruins avenged an earlier Mountain Pacific Sports Federation loss to No. 1-ranked UCI with a 25-21, 25-21, 25-23 sweep on Saturday at Crawford Court.
The loss snapped a 10-match win streak for UCI (19-4, 15-4 in conference) and dropped the Anteaters into second place, behind BYU.
BYU (16-4 in conference) visits UCLA (20-5, 14-4) for two crucial MPSF matches Friday and Saturday.
Connor Hughes came off the bench to lead UCI with nine kills, while producing a .444 hitting percentage.
Kevin Carroll had six kills in seven swings (.857), while senior All-American Carson Clark had eight kills and three aces for the Anteaters, for whom senior outside hitter Kevin Tillie had two kills and hit negative .222.