In a rare Friday night match, the No. 1 USC men’s water polo team used a dominant first period to propel themselves to a 13-7 Moutain Pacific Sports Federation road win over No. 10 Long Beach State.

The win marks the Trojans’ 19th in a row, a streak that dates back to last season, as USC remains the nation’s only undefeated team.

The Trojans (17-0, 3-0) took a 4-0 lead after the first period and led 5-0 early in the second period against the 49ers (18-4, 0-1).

Two of the early five goals came from sophomore driver Kostas Genidounias, who led the Trojan scoring effort with a game-high five goals.

“Our defense dominated the first period,” Genidounias said. “They [LBSU] had a really slow two-meter, so we were able to score three goals early in the counterattack. Good defense always leads to good offense, and that was our main weapon.”

The biggest part of the offense was undoubtedly Genidounias, whose five goals tied a career high.

“Our guys did a really good job of getting [Genidounias] the ball in position, which doesn’t always happen,” USC coach Jovan Vavic said. “After his first goal, he was more aggressive and found his confidence.”

The only other Trojan with multiple goals was junior utility Mace Rapsey with two. Junior driver and the Trojans’ leading scorer Nikola Vavic scored one goal in the first period, keeping alive his streak of scoring in every game this season. The goal was the 139th of Nikola Vavic’s career, moving him into 11th on the Trojans’ all-time career scoring list.

The score indicates otherwise, but the Trojans let off the gas after their initial spurt and let the 49ers back into the game after running out to a 5-0 lead. Once up 6-1, the Trojans had a 6-on-5 opportunity in the second period with the chance to extend their lead to 7-1 and knock the 49ers down for the count.

Instead, USC turned the ball over and the 49ers quickly scored to pull to 6-2, a two-goal swing. Long Beach State scored early in the third period to pull within three goals at 7-4, but two quick goals from Genidounias and senior driver Tobias Preuss put the feisty 49ers away for good.

“If they had scored another to pull within two, we would have been in for a brawl,” Jovan Vavic said. “Luckily, Kostas scored a goal every time we needed one.”

The Trojans had one of their strongest opening periods all season, but the team knows that failing to put opponents away could become a bigger issue later in the season.

“We need to keep our concentration as the game goes on,” Genidounias said. “We gave them a few easy goals when we lost our focus. Friday, it was LBSU. But against a top opponent, our lack of focus might cost us a really great game down the road.”

Coach Vavic is proud of the way the Trojan offense finished shots on Friday, but he said there’s always room for improvement.

“We are not looking around to see what teammates are doing at all times,” he said. “We must be more aware.”

The Trojans are fully immersed in the midseason grind at this point, and this upcoming week will not do the team any favors.

USC will travel south to take on No. 6 UC Irvine on Thursday before returning home to host No. 5 University of Pacific and Cal Lutheran in a Saturday double-header, the squad’s first home matches after eight consecutive matches on the road.