BERKELEY, Calif. -- Princeton might have to not only play a perfect game, but also have USC stumble to win Saturday. And UC-San Diego knows it, too, is probably a longshot when it takes on UCLA in the other NCAA Collegiate Men’s Water Polo Championship semifinal.

But the underdogs aren’t complaining.

“This is the show,” UCSD coach Denny Harper said. “This is the pinnacle of our sport. To be a part of the [championship] is fantastic. “

“I think for both of us, us and UC-San Diego, it’s a big task,” Princeton coach Luis Nicolao said. “We’re playing against USC and UCLA, two dominant programs over the years, so both of us have nothing to lose, so play the best we can and see what happens.

The first match Saturday in Cal’s Spieker Aquatic Complex pits top-seeded and three-time defending champion Southern Cal (24-3) against No. 4 Princeton (22-9.) Then second-seeded UCLA (23-4) takes on third-seeded UCSD (17-9). The losers play a consolation match before the championship match on Sunday.

USC, gunning for an unprecedented fourth consecutive title, held onto the top seed despite losing to UCLA 10-9 in the Mountain Pacific Sports Federation tournament final last Sunday.

USC earned the tournament’s at-large bid, while Princeton defeated Navy 10-7 on Nov. 20 to win the College Water Polo Association’s Eastern Championships and its automatic bid. UCSD defeated UC Davis 8-7, also two weeks ago, to win the Western Water Polo Association’s automatic bid.

“My guys are absolutely giddy to have won our conference championship and to be here and be one of four teams that can actually say they are competing for a national championship,” said Harper, named WWPA coach of the year for the 16th time.

Conversely, the veteran finishing his 32nd year at UCSD knows he has to keep that giddiness of his youthful Tritons under control.

“I’ve yelled at them quite a bit the last week or so,” Harper cracked. “But I like where we’re at. Obviously when we’re playing a powerhouse like UCLA, shoot, we’re monumental underdogs, but that’s OK. It kind of defines our program anyway.”

In their previous meeting, at UCSD on Nov. 6, UCLA beat the Tritons 9-4.

“They’re bigger, stronger, faster and a little more experienced. But other than that,” Harper said, with a laugh, “we think we can beat ’em.”

The key, he said, will be to control water polo’s version of the low post, the hole set.

“Their two-meter offensive players are very, very good. If the ball goes to set, it’s going to be a problem for us.”

It’s not that simple, however, because 10 different players scored in that 10-9 win against USC.

“We have to play a pretty well-orchestrated zone defense,” Harper said. “And then at the same time, making sure that knowing that they’ve got a couple of great outside shooters. There’s poison all over the pool. We’re just going to have to consider which one we’re going to consume.”

That includes UCLA junior utility player Josh Samuels, who led the Bruins with 46 goals and 45 steals, and junior attacker Griffin White, who added 43. This tournament also is a homecoming for UCLA senior Cullen Hennessey and to mark the occasion, the Bruins foresaked their practice time at Cal to work out Friday at Hennessey’s prep alma mater, Sir Francis Drake High School.

UCSD is led by senior Graham Saber. The senior scored a whopping 80 goals this year for a program making its first semifinals appearance since 2006. UCLA, rather, is trying to win its first title since 2004 and ninth overall and a return to the title match after missing out last season.

Whereas USC practiced Friday with a high degree of intensity, Nicolao cranked up some Bruce Springsteen on the loudspeakers while the Tigers warmed up.

Matt Weber, a 6-foot-6 freshman attacker, leads Princeton with 44 goals. Another freshman, Drew Hoffenberg, scored 43, while Tim Wenzlau, a junior from nearby Palo Alto, has 38.

“It’s going to be a daunting challenge for us, but we’re excited about it,” Nicolao said. In a late-September match at USC, his charges were steamrolled by the Trojans 13-4.

“We learned a lot from that game and that whole trip out here and we’re a different team than we were two month ago,” Nicolao said. “We’ve just go to go out [Saturday] and do it.”

That’s not lost on USC coach Jovan Vavic.

“When we played Princeton at home they were tired. They just finished their trip and they had some tough games. I don’t think that’s the best game for us to judge how Princeton’s going to be,” Vavic said. “Princeton’s a very young and talented team and I think they’re going to be fired up and ready. Plus they had an extra week to prepare for us and that’s another addition to our troubles.”

USC, the top seed for the seventh consecutive season, relies heavily on senior goalie Joel Dennerley, the school’s all-time leader in saves (835) and MPSF player of the year. Senior Peter Kurzeka leads with 38 goals and sophomore Nikola Vavic, the coach’s son, has 36.

“This is really a very special tournament. It’s very exciting and the emotions are so high for the coaches and the players and most of the time these games are so close,” Vavic said.

“So many of the games are won in the last minute, the last 30 seconds, so it’s a very tough tournament to win.”