The white-out turned into a wipeout.

Improbable but true.

In the long, often-bitter rivalry between Hawaii and Long Beach State, Friday night was a stunner, in both its efficiency and brevity. The 15th-ranked Rainbow Wahine needed just 78 minutes to dismantle the 49ers, more than avenging their lone conference loss suffered at The Pyramid last month.

Led by senior Annie Mitchem’s career-high-tying 13 kills and 10 from junior middle Emily Maglio, Hawaii swept Long Beach State 25-13, 25-15, 25-16 at the Stan Sheriff Center. The victory gave the Wahine (17-5, 10-1) sole possession of the conference, with the 49ers (16-9, 10-2) falling into second.

It was a don’t-pinch-me moment for an all-too-short time for the white-shirt-wearing crowd of 6,730 — as well as for Hawaii coach Dave Shoji.

“I don’t think anyone around the country will believe the scores,” said Shoji after the Wahine notched their first home sweep over the 49ers since 2012. “I was hoping that Jeff (associate coach Hall) didn’t pinch me. We couldn’t believe it.

“Everything that we had worked so hard on was being realized. It was unbelievable, just a great performance from everyone.”

It may have been Mitchem’s coming out party as a left-side hitter. She twice was the national player of the year at the two-year college level at Irvine Valley as a middle blocker but has become more comfortable on the outside, as evidenced Friday night.

Mitchem had no errors in 21 swings, hitting .619. Hawaii’s diversified attack, run by freshman setter Norene Iosia, often meant Mitchem had no 49ers blocker up, a situation of which she more than took advantage.

Mitchem also got in several stints in the back row, her bomb from behind the 3-meter line in Set 1 making it 17-11, and hinting at the future use of that attack option. That play, as well as the effective slides run by Maglio, all hinge on passing.

It was something the Wahine focused on after having admittedly their worst passing game against the 49ers on Oct. 8. Maglio, who hit .000 with just two kills in that match last month, had her own personal focus.

“I played pretty bad the last time and I wanted to show I could play better,” said Maglio, who hit .450 with just one error. “I think Norene did a great job and our passing was a contributing factor.

“It’s a huge win for us. If we lost, we might not make the NCAA tournament.”

There was pressure on Hawaii to win the rematch, which will go a long way to claiming the Big West title and the automatic berth into the NCAA tournament. The line of thinking was that, had the Wahine lost out to the 49ers for the championship, Hawaii was in danger of not getting an at-large berth due to its low Ratings Percentage Index rank (currently 40).

Now the pressure is on for Hawaii to win out, starting with today’s 7 p.m. match against Cal State Northridge (7-15, 3-7). It might be considered a trap game, but “as Dave said in the locker room, we can now focus on CSUN,” Maglio said. “We need to bring the same energy.”

Maglio, who had two kills last month at The Pyramid, had three as Hawaii took a 15-10 lead in Set 1. At 16-11, Mitchem camped out on the service line, her 6-0 run capped by an ace that made it 22-11.

It didn’t get much better for the 49ers in Set 2. Taylor created her own zip code from the service line starting at 2-1. When the smoke cleared, she had three consecutive aces and The Beach was out of timeouts at 11-1.

The Wahine led by as many as 13, the last at 20-7, before the 49ers strung together two three-point runs to help make it respectable at 22-14. A net violation gave Hawaii the 2-0 lead and the match wasn’t even 45 minutes old.

Set 3 was a little tighter, with Mitchem trading kills with 49ers senior Nele Barber. With Hawaii leading 15-10, Taylor’s extended stint at the service line included two aces that pushed it to 20-10.

At 22-11, “I think that’s when I thought we had it,” Shoji said.

Barber, who had 20 kills last month against Hawaii, finished with nine kills and 13 digs. Junior middle Ashley Murray, who had 17 last month, finished with five while hitting negative-.048.

The Wahine won the dig battle 48-38, with junior libero Savanah Kahakai finishing with 16. Hawaii also outblocked The Beach 8-3, with Maglio in on four.

Notes

Tonight’s match is Hawaii’s “Think Pink,” with fans encouraged to wear pink for breast cancer awareness … The Big West has decided that the protested match between Long Beach State and UC Irinve will not be replayed from the point of the protest. The match, originally won by the 49ers 3-2, has been declared a “no contest.”