Their fortunes changed in a flash.

One moment, the UCLA men’s volleyball players were celebrating a trip to the Final Four.

The next, they were mourning the end of their season.

That’s how quickly the momentum shifted Saturday night after what appeared to be the winning point was wiped out by an official review during the Bruins’ NCAA Tournament quarterfinal against UC Irvine.

Given new life, the unseeded Anteaters went on to complete the comeback, knocking off top-seeded UCLA, 25-23, 19-25, 25-23, 19-25, 16-14, at Pauley Pavilion.

How big of an upset was this?

The Bruins (29-2) had lost just once previously this season, with their only other setback coming against Pepperdine a month ago.

“Being honest,” said UCLA senior outside hitter Zach Rama, his eyes reddened with sadness, “I don’t think it’s anything any of us expected just because of how confident we are and our ability to play together. I don’t think it’s fully hit me yet.”

Rama’s attack error on match point sparked a wild celebration for UC Irvine (20-8), which had trailed 8-4 in the fifth set and appeared momentarily beaten after an earlier match point had been awarded to the Bruins before being reversed.

Anteaters coach David Kniffin said he was confident the replay would given his team the critical point because he had heard a UCLA player touch the ball on the play.

“But sound doesn’t carry on a challenge review system,” Kniffin said, “so you never know what the camera is going to pick up. But, for me, it wasn’t even if we got the touch or not, it was about sustaining belief.”

In the Bruins’ huddle, there was determination to not let the call beat them twice.

“We did talk about being able to move on even if the call was to be overturned,” senior setter Andrew Rowan said, “so do our best to bounce back from a call like that.”

This was already an unusual situation for the Bruins, who were forced to rally to force the fifth set. They had trailed 2-1 only three times previously this season, including a comeback victory over the Anteaters on Feb. 28 that they won in five sets.

After the reversal on match point pulled the Anteaters to within 14-13, an attack error on UCLA middle blocker Cameron Thorne tied the score.

The Bruins then unsuccessfully challenged a kill by UC Irvine’s Andreas Brinck, which gave the Anteaters match point. They capitalized on Rama’s attack error that sailed out of bounds.

As their fans roared in approval, the Anteaters’ reserves bounded onto the court and senior William D’Arcy pulled the front of his jersey over his head in celebration.

Meanwhile, the Bruins were left to contemplate a Final Four that will be held without them on their home court. UC Irvine will play fourth-seeded Ball State in one semifinal May 9 at Pauley Pavilion, and third-seeded Long Beach State will play second-seeded Hawaii in the other semifinal.

“I mean, it’s obviously tough,” Rowan said. “It’s the first time we haven’t been past this game in our collegiate career, so it’s tough. It hasn’t really set in yet.”

UCLA’s seniors had been part of two championships before finishing as runners-up last season. There would be no happy ending in their farewell season.

“I’m incredibly sad for them,” Bruins coach John Hawks said. “We had an incredible run, and I’m sorry to see it end.”