A “gut” feeling and gutty pitching fueled the Hawaii baseball team’s 5-1 victory over Tulane at Les Murakami Stadium.

The outcome, before 1,799 fans, completed the Rainbow Warriors’ sweep of the three-game nonconference series. The ’Bows, who improved to 12-8, have won 15 of 18 Sunday games dating to last season. The Green Wave fell to 6-18.

UH head coach Rich Hill went with his instincts — and scouting reports — in giving the left-field start to struggling outfielder Sean Rimmer. The Yavapai College transfer struck out in seven of his first 13 UH at bats.

“Gut feel,” Hill said of starting Rimmer. “Pitching matchup where (right-hander Ricky Castro) just matched up a little better with (Rimmer). Combination with a couple other guys scuffling a little bit. He just took advantage of the opportunity.”

With one out in the fifth, Rimmer belted a solo home run to left to break a 1-all tie. It was the first extra-base hit of the season for Rimmer, who hit 18 homers at Yavapai last year.

“In the film room, I knew right away it was going to be a perfect matchup for me and my swing,” Rimmer said of the middle-of-the-plate fastball. “It happened. I’m glad it did.”

In the seventh, Rimmer hit a double — off a Michael Lombardi fastball — to the base of the fence in left-center that eventually became UH’s third run. Tai Walton, pinch-running for Rimmer, scored on Ben Zeigler-Namoa’s single to right-center to make it 3-1.

On the play, Jordan Donahue was called out at the plate on a relay from right fielder Teo Banks to first baseman Brady Marget to catcher Seth Beckstead. There was hold-me-back chatter following the contact between Donahue and Beckstead.

“He was blocking the whole plate, and I just slid right in,” Donahue said. “It’s kind of what happened. Nowhere else to go. I thought it was obstruction. He was blocking the whole entire plate. It is what it is.”

Tulane coach Jay Uhlman offered this perspective: “When the ball’s coming and you’re in the process of catching it, you’re able to go catch the ball. That’s just a good baseball play. Donahue slid hard, and our guy held on to the ball, and made the tag. To me, it’s a good play.”

Third baseman Kyson Donahue’s second home run in as many days — a two-run drive over the fence in right — extended the ’Bows’ lead to 5-1 in the eighth.

“I knew (Colin Reilly) had a little cutter-ish fastball,” said Donahue, who hit .417 with eight RBIs during the series. “I was expecting that first pitch, and I got it belt high, and put a good swing on it.”

Hill said: “You can feel the air go out of them on the other side after that home run.”

For the third game in a row, UH pitchers dominated. Alex Giroux, who pitched two-thirds of an inning of relief on Friday, allowed three hits in four scoreless innings in his first start since UH’s season-opening series. Ben Zeigler-Namoa, Harrison Bodendorf and Connor Harrison pitched the rest of the way.

After throwing 33 pitches on Saturday, Bodendorf came back to allow one hit in two innings. “It’s nice to see him in that role and do that,” Hill said.

Harrison, who had a four-out save on Friday, pitched the final two innings on Sunday. “Connor was Connor,” Hill said of Harrison, who threw strikes on 16 of 22 pitches for his fifth save.

Harrison has embraced the closer’s role. “I’m ready to go every day,” he said. “Gotta be ready, gotta be hot, get the body ready. … Just gotta go out and compete. That’s what I love doing. And pounding the zone.”

Uhlman had hoped for a better showing. “It’s hard to win games when you only score one run in each game,” he said. “We had some things that didn’t go our way that could have changed the complexions of innings. My hat’s off to (the ’Bows). They played well.”

The ’Bows resume league play with this coming weekend’s road series against Cal State Fullerton.

“We’re rolling,” Harrison said. “I think we’re a scary team, so look out.”