Seven goals for the USC men’s water polo team last weekend clinched a victory over Cal in dramatic fashion to end the regular season, and when the postseason begins tomorrow, seven will once again be the magic number for the Trojans (21-4, 6-2 MPSF). With six straight NCAA championships under their belt, the Trojans’ path to lucky number seven begins tomorrow against UC Irvine, as they’ll first have to go through the Mountain Pacific Sports Federation tournament in order to claim a spot in the NCAA tournament.Goalasaurus · Senior driver Rex Butler is USC’s second-leading goalscorer this season with 39. Butler also has 11 multi-goal games. – Brian Ji | Daily Trojan“All I’ve got to say is that we’ve got to win all the games [at the MPSF tournament] to secure a spot in the NCAAs,” senior driver Kostas Genidounias told the Pac-12 Network after the Nov. 15 game against Cal. “We [have to] keep playing like this — for the past two weeks, we’ve been playing excellent defense, and we [have to] bring that to the tournament. The goals are coming. We’re a good offensive team. We need our freshmen to step up, not only our seniors, and I think we’re going to have a good postseason.”The No. 3 Trojans edged out No. 5 Cal 7-6 on their Senior Day and regular season finale at Uytengsu Aquatic Center. Following the team’s three-game win streak to finish the regular season, and with the stakes now set at “win or go home,” Trojan head coach Jovan Vavic has no doubt his team can rise to the occasion in the playoffs.“I really like the way we’ve been playing in tough matches when our back is next to the wall,” Vavic said. “We had to play well against Cal. We did. We had to play well against Long Beach State [on Nov. 8], in Long Beach. We did. Every time we have been challenged, we have really responded well.”The 2014 iteration of the Trojan water polo team is younger and less experienced than the championship teams of years past. More than half of the USC team is made up of underclassmen, many of them freshmen entering their first postseason as Trojans.USC will look to senior drivers Genidounias and Rex Butler for both scoring and experience. Genidounias leads the team in scoring with 70 goals on the year and remains five goals away from the Trojan all-time career scoring record, Butler is the team’s second top scorer with 39 goals on the year and both played on the past three championship-winning squads.When it comes to competing in the postseason, the veteran Butler’s advice for his freshman teammates was to keep calm and confident.“You don’t need to add any extra pressure on yourself, because then you’re just going to freeze up out there,” Butler said. “I think they just think [the freshmen] need to stay confident in what they’ve been doing and just approach it like any other game.”Along with his two leading seniors, however, Vavic noted how certain unsung heroes have bolstered the team in big games leading up to the playoffs.“Some of our players are stepping up and each game somebody else is stepping up,” Vavic said. “Last game [senior driver] Marc Vonderweidt had his best game of the season, at the SoCal tournament it was [sophomore driver] Nick Bell, against Long Beach it was [freshman driver] Matteo Morelli. We know that Kostas [Genidounias] is going to be the backbone of our team, we know that Rex [Butler] is going to do his job. But every game it seems like someone else is having a great game, and that’s extremely encouraging.”Friday’s MPSF tournament game against Irvine will be the second time in the past three weeks the two sides have met, with the Trojans having defeated the Anteaters 14-10 on Nov. 9. The 21-4 Trojans, however, will not want to overlook the 15-11 Anteaters in Friday’s game — Irvine boasts a lethal scorer in UCLA transfer Lovre Milos, who has found the back of the cage 88 times in 2014 and whom the Trojans will do their best to shut down come Friday.“[Defense] becomes even more important because everybody’s playing their best,” Vavic said. “It’s not a cliché. It’s really that simple — defense wins championships.”The Trojans’ first round clash against the Anteaters will take place at 11:30 a.m. tomorrow at Long Beach. The Trojans will play in the MPSF semifinals Saturday and finals Sunday against opponents to be determined, should they survive and advance so far. Winning the conference tournament would guarantee USC a spot in next month’s NCAA tournament.