Relegated to the role of observer in the second inning, Hawaii coach Bob Coolen watched the Rainbow Wahine softball team open a Big West road trip with a 5-0 loss to Cal State Fullerton on Friday in Fullerton, Calif.

Coolen was ejected arguing a call at first base in the top of the second and spent the rest of the game beyond right field as Cal State Fullerton’s Kelsey Kessler stifled the UH offense in a complete-game victory.

Kessler struck out nine and walked none while holding UH (25-16, 4-6 Big West) to six singles and Cal State Fullerton (24-19, 7-3) moved to within a half-game of conference leader Long Beach State.

The series concludes today with a doubleheader starting at 11 a.m. Hawaii time at Anderson Family Field.

The Titans gave Kessler (13-6) all the run support she needed with a four-run outburst in the bottom of the third inning. Ariana Williams opened the scoring with a two-run single and Alexis Gonzalez followed with a two-run homer off of UH right-hander Brittany Hitchcock (16-8).

“Just a couple mistake pitches by Brittany … and they took advantage of it,” Coolen said in a phone interview.

Cal State Fullerton added a run in the sixth on Bryanna Ybarra’s pinch-hit single to score Zoe Richard, who went 3-for-3 for the Titans.

UH leadoff hitter Danielle Garcielita went 3-for-3, but the Wahine paired hits in an inning just once and slipped 3 1/2 games out of the Big West lead.

Hitchcock, the reigning Big West pitcher of the week, had a run of 16 consecutive scoreless inning snapped and went the distance for UH. She gave up nine hits, struck out three and walked one.

Coolen’s day on the field ended in the top of the second after Angelique Ramos was called out at first after laying down a sacrifice bunt. He argued that the ball was bobbled at first and asked the umpire to consult with the other members of the crew.

“It wasn’t a clean out and he refused to ask,” Coolen said. “I pursued it and he tossed me.”

At Fullerton, Calif.

>> UH (25-16, 4-6) 000 000 0 — 0 6 1
>> CSF (24-19, 7-3) 004 001 x — 5 9 0

Brittany Hitchcock and Callee Heen. Kelsey Kessler and Kylie Padilla. W—Kessler. L—Hitchcock.

Leading hitters—Hawaii: Danielle Garcielita, 3-3. Cal State Fullerton: Ariana Williams, 2 RBIs; Lexi Gonzalez, HR, 2 RBIs; Zoe Richard, 3-3; Bryanna Ybarra, RBI.

Friday
>> Cal State Fullerton 5, Hawaii 0

Today
>> UC Davis at UC Riverside (DH), 10 a.m.
>> Cal Poly at Cal State Northridge (DH), 10 a.m.
>> UC Santa Barbara at Long Beach State (DH), 10 a.m.
>> Hawai at Cal State Fullerton (DH), 11 a.m.

Sunday
>> UC Davis at UC Riverside, 10 a.m.
>> Cal Poly at Cal State Northridge, 10 a.m.
>> UC Santa Barbara at Long Beach State, 10 a.m.