Considering Mike Gerrity hadn’t played competitive basketball in about a year-and-a-half, how much of a contribution could one expect of the point guard when he made his USC debut Saturday at Galen Center?

A lot as it turns out.

The transfer from Charlotte and a former Mater Dei High School star, was cleared academically by the NCAA and Gerrity made the most of it by leading the Trojans to a 77-55 victory over No. 9 Tennessee.

Gerrity had 12 points and 10 assists in handing Volunteers coach Bruce Pearl his worst loss since taking over before the 2005-06 season.

“They're a completely different team with him running the show,” Pearl said. “We knew he could become eligible, but we hadn’t seen him on any tape. His play was a huge factor in their dominating us.”

Gerrity helped the Trojans (5-4) build a 24-point lead in the second half, and go onto its third straight win and first against a ranked team.

Considering Gerrity had not played since March 2008, USC coach Kevin O’Neill said he was “shocked at how well he played.”

Gerrity learned Friday he would be eligible.

“It was incredible, it felt so good,” Gerrity said. “From the moment we tipped, I found my way into the game a few minutes and once I got that comfort (level), it was just unbelievable the rest of the game.”

Alex Stepheson had 19 points and a career-high 15 rebounds, while Nikola Vucevic added 15 points and 10 rebounds for the Trojans, giving them three players with double-doubles.

Scotty Hopson had 16 points to lead Tennessee (8-2), which was out-rebounded 43-21 and had its own four-game win streak snapped. Melvin Goins added 10 points.

Gerrity did most of his work in the first half, handing out seven assists and grabbing three rebounds. Dwight Lewis did his damage after the break, scoring 11 of his 21 points - including all nine during a 9-2 run that made it 59-40.

“I thought at halftime if we could come out and not let them barrage us in the first seven or eight minutes in the second half that we would have a chance,” O’Neill said. “I didn’t think we’d beat them like this.”

Tennessee committed just eight turnovers, but shot a season-low 2 of 22 (9.1 percent) from beyond the 3-point line and scored a season-low 55 points. The Vols entered the week eighth in the nation in scoring offense (85.0) and seventh in 3-point field goal percentage (43.4).

“I couldn't be happier with it,” O’Neill said of his team’s defense. “I thought we did a great job of protecting the paint. I thought our guys did a good job of being in their air space and changing their shots.”

Tennessee struggled early and never found a rhythm, missing their first nine 3-pointers and making just 2 of 14 field goals. The drought allowed USC to jump out to an early 11-5 lead.

“Early in the game we had good looks and we just didn’t make anything,” Pearl said. “They pack it in defensively and we’ve got to be able to make shots.”

Stepheson honored

USC junior forward Alex Stepheson has been named the Pac-10 player of the week for his performance against Tennessee.

Through seven games, Stepheson is second in the conference in rebounds (10.6), first in blocked shots (2.57) and offensive rebounds (4.29). He is averaging 13.4 points per game.

Next on the schedule

USC is in the Diamond Head Classic in Honolulu Tuesday through Thursday.

The Trojans open against Western Michigan Tuesday, then face either Northeastern or St. Mary’s Wednesday.