Almost two-thirds of the way through the season, the No. 1 USC men’s volleyball team has faced a bevy of challenges, but answered all of them with victorious pushes.

Returning · The Trojans’ offensive efficiency took a notable drop against Pepperdine with senior middle block Austin Zahn sidelined with an injury. - Carlo Acenas | Daily Trojan

The Trojans (15-1, 14-1) have amassed nine wins since an early February loss to Pepperdine and have already clinched a Mountain Pacific Sports Federation tournament berth. USC is also three games ahead of second-place Stanford.

USC now faces a crucial home match with the Waves (8-11, 4-11), which served up the Trojans with their only loss this season.

“Every match down this final stretch is important,” said senior setter Riley McKibbin.

In the loss last month, the Trojans were also without starting middle blocker Austin Zahn due to injury. Zahn’s absence took away from the Trojans’ efficiency — the team finished with a .292 hitting average, considerably lower than the season .357 average.

“We didn’t pass the ball well last time and didn’t serve well,” said USC coach Bill Ferguson said. “And to their credit, they served the ball exceptionally well last match.”

Because of Zahn’s absence, the three pin-hitters — senior opposite Murphy Troy, senior outside hitter Tri Bourne and junior outside hitter Tony Ciarelli — finished with 55 of the team’s 65 kills.

“It sucks sitting on the bench during a loss,” Zahn said. “I’m definitely fired up and am going to make sure my presence is felt.”

With Zahn in the lineup, the Trojans are the most efficient offensive team in the MPSF, sporting a league-leading .357 hitting percentage. McKibbin leads the conference with 12.98 assists per set.

The Trojans are also the most stingy defensive team in the conference, allowing a league-best .244 hitting percentage for their opponents. They also lead the league in digs, with 9.90 per set. This includes freshman libero Henry Cassiday, who is second in the league in digs, and McKibbin, who ranks seventh.

“I really like how we keep improving,” Ferguson said. “Our season, especially the last two weeks, have played out just how we wanted it to.”

USC worked through a nine-game break between the Harvard match played during spring break and Friday’s match against Pepperdine.

In the three weeks before the break, USC played two sets of back-to-back matches and had three of six matches go to five sets.

“We had some tough, tough matches right before the break,” Ferguson said. “They took a lot out of us physically. With the extra time, we’ve been able to increase the intensity of our weight training and get to another level strength-and-conditioning-wise.”

Although the Trojans have not allowed the thought of revenge to overshadow their dutiful preparation, they recognize their record is tarnished by the February match.

“We’ve beaten UCLA, [assistant coach] Jeff Nygaard’s alma mater, and Cal State Northridge, [assistant coach] Cameron Green’s alma mater,” McKibbin said with a smile. “The only coach we haven’t beaten so far is [assistant coach] J.J. Riley. It’s almost personal.”

First serve is at 7 p.m. at the Galen Center.