MORAGA, Calif. - Pacific hit five home runs including two by Matthew Tarantino, but Saint Mary's took game one of a three-game West Coast Conference series from the Pacific baseball team Friday, 15-9.

Lucas Halstead, Ryan Schalch and Danny Mayer also homered for the Tigers, as all nine runs came in on home runs, highlighted by Schalch's grand slam.

Tarantino has hit three home runs in his last five at bats, doubling his total entering the week to six.  Mayer's eighth homer of the year ties him with James Free II for the team lead. Halstead hit his fifth, while Schalch's grand slam was his third home run this season.

But Saint Mary's posted an eight-run sixth inning to turn a 8-3 Pacific lead into a three-run Gael advantage. Saint Mary's scored 12 runs in their final three innings at the plate.

Tarantino opened the scoring with a solo homer to right in the first inning, but the Gaels answered back with a run in the bottom half on an RBI groundout from Zach Kirtley to plate Joey Fiske, who reached on a two-base error and was sacrificed to third.

Mayer added a solo home run to center field in the top of the second, but the Gaels plated two in the bottom of the frame on a homer from Edward Haus, a double by Austin Chauvin and a squeeze bunt from Conor Thane for a 3-2 Saint Mary's lead.

In the third, Tarantino walked with two outs, and Free singled through the left side. After a walk to Halstead, Schalch delivered the big blow, with a grand slam to give the Tigers a 6-3 lead.

Halstead followed a Free single in the fifth with a two-run homer to left as Pacific led 8-3 after five innings.

But after five strong innings in which he allowed two earned runs on four hits, the Gaels got to Pacific starter Ryan Shreve in the sixth. Kevin Milam opened with a single and after a double from Haus, Jackson Thoreson plated the first run on a sacrifice fly. Chauvin doubled to left center for another run and after a hit by pitch and an error, Justin Gionvannoni replaced Shreve. He was greeted by a two-run single from Fiske, and then Kirtley added a two-run double. Another run came home on an RBI groundout from Milam, and Haus added an RBI single before Ed O'Bannon III entered and coaxed a groundout to finally end the frame.

Tarantino pulled Pacific within 11-9 with his second solo homer in the eighth. But Saint Mary's tacked on four in the bottom half on RBI singles from Chauvin and Joe Vranesh, a sacrifice fly from Fiske, and a double-steal with runners on the corners.

Shreve took a no decision, as he allowed six earned in 5.1 innings with a pair of strikeouts. Giovannoni was saddled with the loss, falling to 0-1, allowing one earned in a third of an inning. O'Bannon finished up the final 2.1 innings, with the four-run eighth on his ledger.

Cameron Neff (4-0) picked up the win for the Gaels in relief of starter Johnny York. York allowed six earned runs in four innings, on six hits. Neff allowed two earned runs in two innings of work, walking three. Ty Madrigal tossed two innings, allowing a run, while Milam pitched the ninth for the Gaels, retiring the side in order.

Pacific falls to 13-22 on the season, and 2-14 in West Coast Conference play. Saint Mary's improves to 24-13 overall and 7-6 in the WCC.

Game two of the series is Saturday at 1 p.m.