An opportunity for a series-opening victory at Big West mainstay Cal State Fullerton got away from the Hawaii baseball team.

UH lost a four-run lead, then the game as the Titans walked it off, 7-6, on Jack Haley’s two-out double to the centerfield wall at Goodwin Field in Fullerton, Calif., on Friday night.

The Rainbow Warriors struck immediately with a two-run double by Jacob Igawa, and pushed it to 5-1 in the fourth against Titans starter Tyler Stultz, but UH’s two best relievers could not make the lead stand up.

"I was just going up there looking for a pitch I could drive," Haley told CSUF athletics of his decisive at-bat against Rainbows closer Connor Harrison, which yielded the first walk-off hit of his life. "Honestly it was just a tough day for me in general and our team continues to fight. I was just happy we could come back at the end there."

UH (12-9, 2-2 Big West) lost for the first time in the last five starts of left-hander Harry Gustin, who exited after tossing 4 2/3 innings with two runs, seven hits and two walks allowed. He struck out five.

The Titans (13-8, 6-1), winners of six straight and nine of 10, were coming off a rousing 15-5 nonconference win over No. 12 UCLA on Tuesday. CSUF coach Jason Dietrich was thrown out of Friday's game in the sixth inning after arguing a strikeout against Brendan Bobo, but that was when the Titans did their most damage.

"I had a little disagreement with the umpire," Dietrich told CSUF athletics on his first career ejection as Titans coach. "I thought his (strike) zone was just a little different tonight. So I just let him know that and he felt he needed me to leave, so he tossed me."

Alex Giroux came on in relief of Gustin in the fifth but was tagged for four runs in the sixth, including his first home run allowed of the season, to Moises Guzman, as the Titans eked ahead 6-5. Guzman's first home run of the season came on his birthday.

UH tied it up at 6-6 on in the seventh. Jared Quandt led off with a single, got to second on Stone Miyao’s walk, and reached third on Naighel Calderon’s sacrifice bunt. Jordan Donahue scored Quandt on a groundout to short.

Connor Harrison worked the last three innings for UH and nearly got the Rainbow Warriors into extra innings. But Guzman reached on an error by third baseman Kyson Donahue and Haley’s double off the wall scored Guzman from first as the Titans poured out of the dugout.

Kyson Donahue extended his hitting streak to 13 games with a single up the middle to lead off the third.

Randy Abshier (2-1, 3.12 ERA) is set to take the mound for UH in Game 2 of the series at 2 p.m. Hawaii time on Saturday.

Brian McInnis covers the state's sports scene for Spectrum News Hawaii. He can be reached at brian.mcinnis@charter.com.