Dwight Powell added 15 pounds to his frame and used it to throw his weight around.
Powell scored 18 of his career-high 27 points in the second half as Stanford beat San Francisco 74-62 Friday night in the season opener for both teams.
Powell, who added seven rebounds and a blocked shot, left the game with an apparent injury with 1:35 remaining but said it was just cramps.
"We worked out a lot during the off season," Powell said. "Right now, everything feels good."
Josh Huestis, who gained 10 pounds through weight training during the offseason, added 11 points and nine rebounds for the Cardinal, who improved to 23-2 in their past 25 openers.
"Right now, my confidence is high," Huestis said. "I know what I'm doing in various roles, and we have the camaraderie."
Freshman Avry Holmes came off the bench to score 17 points, Cole Dickerson added 11 points and a career-high 18 rebounds and De'End Parker had 13 points for the Dons.
"Offensively, we were inept," San Francisco coach Rex Walters said. "Guys were trying to do too much, and we got away from what we wanted to do."
The game marked the return of Mark Madsen, who played nine years in the NBA after graduating from Stanford. The two-time All-American joined the staff of coach Johnny Dawkins.
The Dons produced their first 20-win campaign in 31 years last season. Cody Doolin is their lone returning starter, with Dickerson another top returner.
"We have some work to do," Walters said. "We'll get better."
Stanford, meanwhile, returned four starters from its NIT title team. The Cardinal were picked to finish fourth in the Pac-12.
In a game at Oracle Arena, the Cardinal opened the second half on a 14-3 run, with Powell scoring half of the points, to open a double-digit lead.
"He was terrific," Dawkins said of Powell. "He did a great job. It's good to get going."
Stanford held a 14-point advantage midway through the first half before the Dons went on a 24-9 run, led by Holmes, who hit four of his first five shots, to take a 31-30 lead.
The Cardinal hit a shot at the buzzer to take a 32-31 edge into intermission.