"I don't know. I can't feel it yet," the sophomore quarterback said, about an hour after his debut as a starting quarterback was complete. "Tomorrow I'll feel it. It's awesome, though. So fun. Unbelievably fun."
The same could be said for the sensation coach Pete Carroll and some of the Trojan faithful felt watching Sanchez play, in Saturday's 20-13 victory against Arizona. His numbers were not exactly Heisman-like (19-of-31 for 130 yards and a touchdown), and he is the only quarterback of the Carroll era to throw a ball to the other team in his debut (the Wildcats intercepted him twice), but he made some crucial plays, never lost his composure and displayed a knack for getting dirty. Isn't that the key to every fan's heart?
"He's a blast to watch," Carroll said. "He's fun; he's energetic; he's upbeat. He was scrambling for his life out there at times and missing reads - all kinds of stuff. But he found a way to get it done."
Following Joe McKnight's 45-yard fourth-quarter punt return, Sanchez connected with senior tight end Fred Davis for his longest completion of the day - a 25-yard strike down the left seam that put the Trojans ahead 17-13.
Sanchez started in place of John David Booty, who broke the middle finger on his throwing hand in last week's loss to Stanford. Coaches protected the first-timer with conservative playcalling, and Carroll expressed a special need to take pressure off Sanchez after the sophomore threw a pair of first-half interceptions.
"Mark was smiling the whole time," said fullback Stanley Havili, Sanchez's roommate. "You could tell Mark was having fun."
The quarterback admitted it was a bit of an act. He gave thanks to his coaches and teammates, particularly Booty, for keeping his spirits up and maintaining their confidence in him.
"Inside, it was killing me," he said of the interceptions. "It was eating away."
Then came the second half. Sanchez found a comfort zone, the playcalling loosened up and the sophomore began to shine. Never mind the numbers - 11-of-15 passing for 74 yards and the touchdown - Sanchez began making the plays that had fans calling for a post-victory leap into the stands. He obliged.
He began endearing himself to Coliseum crowd on the team's third drive of the third quarter. On a third down and seven from his own seven-yard line, Sanchez rolled right after the pocket had collapsed, dropped deep into his own end zone and fired a pass up the sideline to Patrick Turner for a first down. After pushing the pile on a quarterback draw, to convert on third down and one, Sanchez executed an impressive incompletion on the next play.
With Antoine Cason - who had grabbed the first interception - blitzing untouched from the corner, Sanchez ran backward, stiff-armed the defender to give himself a free moment, and fired the ball out of bounds to avoid a sack.
Then, just before the third quarter ended, Sanchez almost recorded his first tackle, taking down linebacker Spencer Larsen, who had recovered a Davis fumble. Upon review, it was clear that Davis had been down by contact, and the call was overturned. But Sanchez, who never played defense in high school, still managed to display a knack for the safety position.
"They had a wall set up, so I knew I was going to get smacked if I tried to (go through them)," Sanchez said. "I waited for the right moment. Two of their big D-linemen were probably looking for me. One of them smacked me earlier, on that interception to Cason. I just kind of knifed in there and tried to just trip him out, like (Ben) Roethlisberger did," in the second round of the 2006 playoffs.
A few series later, when Larsen lay on the field briefly with an injury, Sanchez walked over and applauded his opponent.
The quarterback capped his performance with a 10-yard run on third down and seven from the Arizona 12, late in the fourth quarter.
"The scramble was ridiculous," Carroll said. "I'm going to kill him for where the ball was. It was all over the place when he was scrambling. But he made a great play right there."
The pass broke down almost immediately, and Sanchez took off. He sidestepped Larsen near the 10, then lowered his head into safety Nate Ness for the final few yards.
"I was like, 'There's no way I got the first down yet,'" Sanchez recalled. "It seemed too far. So I'm trying to peek out my left side of my facemask and see where the sticks are, as I'm going down. I just tried to drive a little bit extra and then reach out the ball.
"As soon as I looked to the left and it was on the ground, I'm looking through guys' feet and cleats and stuff. Then, I see the sticks, and I was like, 'Oh God, yes. We got it.'
"So I got up quick and let them know I was all right. And we scored."
Don't they teach him how to slide?
"We'll probably talk about that quite a bit," Sanchez said with a smile. "I can't keep doing that for whatever - the next six, seven games."
Sanchez's opportunities might not be that plentiful. But Carroll said that Booty, who was supposed to serve as the No. 2 quarterback Saturday, could not throw a ball in warm-ups. The coach said it could be three weeks before the finger fully heals.
USC heads to Notre Dame next weekend, and Carroll said the Trojans would prepare with Sanchez as the starter.
"(There was) a lot of pressure on this game - as much as he's going to feel," Carroll said. "Until the next game we play."
Jonathan Kay can be reached at Jon@USCFootball.com