LOS ANGELES — Matt Leinart is enjoying himself again. It's obvious in his demeanor and body language.
Leinart, last year's Heisman Trophy winner, passed for 245 yards and four touchdowns in the first half Saturday night, leading top-ranked Southern California to a 51-21 victory over Stanford.
The fifth-year senior has completed 66 of 88 passes for 824 yards and 11 touchdowns with only one interception in the three games USC has played since its dramatic last-second 34-31 victory at Notre Dame.
"I'm just playing and having fun. I got away from that for a couple weeks, trying too hard to do things," Leinart said. "The last couple weeks, just been having fun. I'm sure the guys around me, they'd agree.
"My arm feels better than ever. Also, it helps that I'm getting all day to throw out there."
USC had to come from behind three times on the road in a span of four weeks to beat Oregon, Arizona State and Notre Dame. Despite leading his team to those wins, Leinart didn't seem to be enjoying himself much — especially after the games at ASU and Notre Dame.
He certainly seems happier now, and it's been reflected in his performance on the field.
"Matt, he's doing really good right now," teammate Reggie Bush said. "He's back to his old self. When he's doing well, we're all doing well."
Leinart guided the Trojans to six touchdowns and a field goal in the first half, when USC took a 44-7 lead over Stanford.
"Matt did everything he was supposed to do," coach Pete Carroll said.
The 44 points were the most scored by the Trojans in a half since they had 49 in the second half of a 55-24 victory over Notre Dame in 1974. USC has scored 50 or more points a school-record five times this season, including each of its last three games.
"It's been a big deal in this program about how we finish," Carroll said. "Now it's the fourth quarter of the season. We've got three huge games coming up. We're just really fired up about it."
The Trojans (9-0, 6-0 Pac-10) have won 31 straight games, their last loss a 34-31 overtime setback at California on Sept. 27, 2003. They play the Golden Bears in Berkeley next weekend.
"Last time we were up there, we all know what happened," Leinart said.
After playing at Cal, the Trojans host Fresno State on Nov. 19 and UCLA on Dec. 3. If USC wins all three, it's a virtual cinch to be playing in the Rose Bowl for the national championship on Jan. 4.
The Trojans also have a 25-game winning streak at home and a 21-game streak against conference opponents. Their last loss at the Coliseum was a 21-16 setback to Stanford on Sept. 29, 2001 — Carroll's fourth game as their coach.
Leinart completed 22-of-28 passes for 259 yards without being intercepted. He played just one series in the second half before being relieved by John David Booty, who went 7-of-10 for 86 yards.
Stanford (4-4, 3-3) hadn't committed any turnovers in its previous four games. But the Trojans forced five, including three in the first half, to set up two touchdowns and a 21-yard field goal by Mario Danelo.
"We know that our biggest opponent is ourselves," said Bush, who gained 113 yards on 12 carries to surpass the 1,000-yard mark for the first time in his three-year career at USC.
"We feel like if we go out there and dominate and play like we know how, then the rest should take care of itself," Bush said. "Every call we make, we feel like we'll take it the distance."