College volleyball’s biggest party, the Final Four, is being played in Seattle. Would Washington be in attendance? Only if the Huskies could beat a physically imposing opponent, USC, on the Trojans’ home court in an NCAA regional final Saturday night. And things looked grim.

Washington lost the first two sets, looked error-prone (the team averages 15 attack errors per match, but had 16 after two sets) and at one point sent a wobbly serve under the net.

Meanwhile, USC’s Ebony Nwanebu, the Pac-12 freshman of the year, hammered Washington’s defense with 16 kills in the first two sets, on her way to 30 — all without an error.

“We tried everything,” UW coach Jim McLaughlin said, “but we just could not stop her.”

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Time to despair?

“We were down 0-2, and any team could panic and start thinking, ‘Oh, it’s over,’ ” said sophomore Cassie Strickland, who had UW’s hot hand early. “But looking around the locker room (at intermission) there was no doubt in anyone’s eyes. We were just going to go out and battle for every point.”

And so they did, rallying behind Krista Vansant’s career-high 38 kills (with 14 in the fourth set alone) to defeat sixth-seeded USC in a nearly three-hour match, 26-28, 23-25, 25-22, 25-18, 17-15.

“It might be adrenaline, I don’t know,” Vansant said, searching for an explanation for her big night. “I do it for my teammates. I do it for this program and what UW volleyball stands for.”

Added McLaughlin: “She was a stud, very aggressive. The thing I liked about her most was she hit a couple of balls out of bounds at critical times but then made a perfect pass, a nice dig, hit a great serve. It didn’t affect the other parts of her game.

“That’s really the sign of character and all the things we talk about. Anybody can do it when you’re going (well). But to respond to that adversity is really a big deal.”

The victory put Washington (30-2) into its first Final Four since 2006 and keeps the Huskies in pursuit of their first national title since 2005. The Huskies face second-seeded Penn State (32-2) Thursday at approximately 6:30 p.m. after top-seeded Texas (27-2) meets 12th-seeded Wisconsin (27-9) at 4:30. The championship match is Saturday at 6:30 p.m.

Big stats worth noting in the win over sixth-seeded USC (29-6): Vansant also had a career high in digs with 30; on offense, she had 81 swings and hit .346; UW had five aces to USC’s two; USC had no blocks in the final three sets after posting nine in the first two.

Big moments: A momentum-shifting 5-0 UW run in the third set to erase a 12-11 USC lead, keyed by Melanie Wade’s flat, sneaky-fast serves; the Huskies twice withstanding USC match points in the final set; Gabbi Parker entering the game late in the fifth set and, at 15-15, posting back-to-back kills to end it.

“Parker came up and whispered in my ear, ‘I’ll kill it if you get me in there,’ ” McLaughlin said. “Any time a player does that, it gives you incentive to go, ‘OK, you better do it.’ Some of this coaching stuff is just a gut feeling. We got her in there and she did a good job.”

So what changed after intermission? For McLaughlin, it was his team’s ability to withstand the ebbs and flows of the match.

“Just hold course, and eventually it will come back,” he said. “We were just a play away. We just had to stay the course.”