LOS ANGELES — UCLA is the most decorated program in NCAA men’s volleyball history, but even the Bruins needed time to readjust to the bright lights of the championship tournament Tuesday.

UCLA overcame a nervy start against Harvard to win 23-25, 25-21, 25-11, 25-21 in the first round of the NCAA tournament on Tuesday. The Bruins (25-7) advance to face second-seeded MPSF rival BYU in a national semifinal on Thursday at 7:30 p.m. at Pauley Pavilion.

“These NCAA tournaments are not always comfortable and sometimes you don’t play great, but you can learn a lot from that experience,” UCLA head coach John Speraw said. “I think we’re going to go back and learn a lot on Thursday.”

The EIVA tournament champion Crimson shocked the Bruins in the first set, winning 25-23 on UCLA’s home court. Harvard (13-14) was making its first NCAA tournament appearance while UCLA leads the nation with 19 championships.

After Christian Hessenauer fought off one first-set set point with a kill, the UCLA senior missed a serve that gave the Crimson the one-set lead. The Bruins had six more kills and a better hitting percentage in the first set, but they couldn’t overcome seven service errors.

“We were bigger, but I felt like at the end of the day, in volleyball, the most important thing is serving and passing,” Speraw said. “They were really good passers, really for most of the night. They were forcing us to really play really good fundamental volleyball.”

UCLA found itself in the second set with five consecutive points that put the Bruins ahead 20-16. After trailing 16-15, UCLA finished the set on a 10-5 run, clinching it on a kill from Micah Ma’a on a Harvard overpass.

The momentum carried over to the third set when the Bruins scored the first five points as they controlled the remainder of the match. UCLA had six blocks in the third set and limited Harvard to a minus-.083 hitting percentage.

The Bruins towered over the Crimson, who have only one player taller than 6-foot-6. UCLA’s middle blockers Oliver Martin and Daenan Gyimah, 6-10 and 6-8, respectively, combined for 20 kills on 29 swings with one error. Martin was perfect with nine kills on nine attempts.

“It’s just incredible,” Ma’a said while looking at Martin’s flawless stat line after the game, “nothing much else to say.”

Hessenauer led UCLA with 22 kills and a team-high 10 digs while assisting on six blocks. Ma’a had 46 assists.

UCLA, chasing its first NCAA title since 2006, was 1-2 against BYU this season, most recently falling in the MPSF tournament championship less than two weeks ago.

“I don’t think it was our best volleyball of the year,” Speraw said of Tuesday’s win, “but I’m hoping that our best volleyball of the year is still ahead of us.”