"I would have been shocked if he didn't play well," Notre Dame coach Mike Brey said. "He's been around us for a while, so it's nice. You lose a six-year senior and we put in another senior who's been in our program. Certainly helped us."
Knight never had scored in double digits in college before, with his previous best being nine points against Sacred Heart on Dec. 19, 2011. He made 8 of 10 shots and pulled down seven rebounds Saturday.
"He's just playing with confidence right now." Grant said about Knight. "A lot of people knew he had it. He's knocking down shots, rebounding, blocking shots, so it's definitely something we need the rest of the year."
Eric Atkins added 13 points and Pat Connaughton contributed 12 for Notre Dame (16-4, 4-3 Big East), which had lost three of four, including a 63-47 loss to Georgetown last Monday.
Notre Dame forward Jack Cooley, who entered averaging 14.8 points, finished with six points and 14 rebounds.
Zach LeDay had 17 points and Anthony Collins added 12 for South Florida (10-9, 1-6).
Notre Dame used a 20-3 run to go ahead 48-40 with 13 minutes to play. Connaughton's 3-pointer broke a 40-40 tie before Knight dunked and Grant connected on a 3 to make it 48-40.
"Sometimes I like to get up there and show [our coaches] I can," Knight said. "It was nice to do that. And the dunk was obviously fun, too."
South Florida got within 52-48 midway through the second half on LeDay's basket. Notre Dame responded by scoring the next six points, a three-point play by Grant and a 3-pointer by Atkins.
Victor Rudd gave South Florida a 37-28 lead with a dunk on the first possession of the second half.
"A very good offensive team," South Florida coach Stan Heath said about Notre Dame. "They're very skilled. Know how to play. Once they got momentum going second half, we just couldn't get it back."
Notre Dame outrebounded South Florida 34-17.