DeRozan scored 14 points in his debut as Southern California's highly touted replacement for Mayo and the Trojans (No. 21 ESPN/USA Today, No. 18 AP) used a second-half run to pull away in a 78-55 victory over UC Irvine on Saturday.
Dwight Lewis had 18 points, Taj Gibson added 17 points and had five of USC's six steals, and Daniel Hackett had 10 points for the Trojans, who lost openers to Cal State Northridge and South Carolina, both in overtime, and Mercer in coach Tim Floyd's first three seasons.
"I kind of liked it for the fact we hadn't beaten anybody in three years," Floyd said.
Mayo was a first-round NBA draft pick after one season. Just like him, DeRozan arrives as a newcomer with the ability to immediately make an impact on the program.
The McDonald's All-American forward averaged 29.2 points as a senior at nearby Compton High. He cracked the starting lineup Saturday, going 6-of-11 from the floor, making both his free throws and grabbing three rebounds.
"It was exciting," DeRozan said. "I didn't want to rush nothing. I wanted to let the game come to me. My time will come."
Floyd couldn't pick one player over the other in comparing Mayo and DeRozan.
"O.J. is a great jumpshooter," he said. "DeMar is a guy who's filling the wings on the break. He's a great finisher. They both have been givers defensively."
With four players in double figures and well-balanced rebounding, DeRozan realizes the load isn't all on him anymore.
"Through high school I always had pressure on me to do a lot," he said. "I don't have to exert myself. The biggest thing I learned is it's fun when we play as a team. Everything will come easy to you if you play as one."
Things certainly flowed for the Anteaters in the first half. They kept it close throughout, leading by two points and shooting 41 percent from the floor.
But the Trojans asserted themselves offensively to open the second half, while also stepping up a defense that limited Irvine to 34 percent shooting in the final 20 minutes.
"They are a very good club, very athletic," Irvine coach Pat Douglass said. "We got back in it towards the end of the first half, but they put it away, which is a sign of a good club."
Leading by six at halftime, USC opened with a 23-7 run to take a 58-36 lead that was never threatened. Gibson scored eight, including two dunks and a basket off his own rebound, while Lewis had five and DeRozan four.
"I wasn't even looking at stats," Gibson said. "It was real important we started the season off on the right track. We were patient."
In the final three minutes, freshman Percy Miller, better known as hip-hop star Lil' Romeo, came off the bench and grabbed one rebound.
Along with Mayo, the Trojans lost their No. 2 scorer, Davon Jefferson, who wasn't selected in the NBA draft. The team is coming off a 21-12 season in which it lost in the first round of the NCAA tournament.
Freshman Leonard Washington hit a 3-pointer before the buzzer that pumped up the Trojans going into halftime. But it was DeRozan who made a lasting impression.
"I loved what I saw," Floyd said. "He really played within himself. He's very unselfish and takes what's given to him. He's really going to help our team."
The Anteaters were 18-16 last season, losing three of their top scorers to graduation. They fell to 1-5 against the Trojans and haven't beaten a Pac-10 school since 2005.