The decision came easy for Keoni Thiim.

Standing on the service line for match point, with the Viking clap in full effect around the arena, “I can’t not rip it as hard as I can,” the University of Hawaii outside hitter said.

“My team behind me is telling me, ‘go for it, end it,’ and I’m just ripping it.”

Thiim indeed rocketed his jump serve across the net — registering at 76 miles per hour on the arena radar gun — for a walk-off ace to cap the top-ranked Rainbow Warrior volleyball team’s sweep of Saint Francis on Wednesday at SimpiFli Arena at Stan Sheriff Center.

The Warriors showed off their efficiency early and depth late with Thiim among the UH reserves who finished out the 25-16, 25-18, 25-23 win before a crowd of 3,260.

Senior outside hitter Kana’i Akana, a serving substitute in UH’s season-opening series with Ball State last week, started the second set and finished with seven kills in 11 attempts.

“It means a lot to me,” said Akana, who subbed in for Spyros Chakas to start the second set. “It’s my last everything, it’s my senior year. So I appreciate the coaching staff for putting me in.

“I tell myself every day I’m behind two really good outsides in Spyros and Chaz (Galloway), so any opportunity I can get I want to make the most of it and I’m just so appreciative of it.”

Thiim, also a serving specialist in his usual role, had three kills in seven swings and tied his career high with three aces in the third set. UH coach Charlie Wade also gave opposite Alakai Todd, libero ‘Eleu Choy and freshman middle blocker Kurt Nusterer starts in the third set. Makua Marumoto also made his first appearance of the season as a serving sub.

“That team beats us all the time,” Wade said of the “B-side” players who take pride in pushing the UH starters in practice. “They can play at a high level, and they work so hard.

“Starting and letting guys play a full set is really important. It makes the practice gym more competitive, it rewards behavior for guys that have gone hard.”

UH’s usual starters did their part in the first two sets with opposite Dimitrios Mouchlias putting away eight kills in 10 swings and outside hitter Chaz Galloway setting a career high with three aces in the first set as the Rainbow Warriors opened a two-match series with the Red Flash with their 12th straight win overall and 21st consecutive home victory.

Setter Jakob Thelle, who had 30 assists for an attack that hit .324, and middle blocker Cole Hogland were the only starters to play the entire match.

Saint Francis opposite Nathan Zini led the Red Flash with 12 kills and middle blocker Brandon Dunz was in on five of Saint Francis’ seven blocks. Middle blocker Thomas Leahey had seven kills in 10 attempts with three errors.

The Warriors (3-0) and Red Flash (0-3), the preseason favorite in the Northeastern Conference, meet again on Friday.

After committing 38 service errors in last week’s series with Ball State, including 23 in the finale last Friday, the Warriors served inbounds at 93.2% on Wednesday with eight aces and just five errors in 73 serves.

Galloway had two of his three aces in a 6-0 UH run late in the first set and Thelle had aces in the second and third sets.

Thiim has played in every set this season as a serving substitute and served inbounds on all 12 of his attempts on Wednesday, saving his hardest delivery for last.

“You won’t see that more than a handful of times all year, that’s next level stuff,” Wade said of Thiim hitting 76 mph.

“I’m so glad he cracked it at the end. That means he’s very clear, very confident and when you get the good toss with that arm … it’s exciting to see where he can go with it because it’s still in a very ascendant phase.”

Along with scoring from the service line, Thiim also relished his opportunity to hit in the front row in the third set.

“It means the world,” the Kalani graduate said. “That’s the first time I got to play a full set. It’s a super good experience for me and a good opportunity to prove what I can do.

“I love serving and being a serving sub is fun, but eventually I want to work my way to be on the floor, so tonight was a good opportunity. I have to let it go and keep working for the next opportunity.”