Florida State held off Virginia 63-56 Saturday, but lost star Chris Singleton with a fractured right foot.
The 6-foot-9 Singleton, the Seminoles' top scorer and rebounder, will have surgery Monday, coach Leonard Hamilton said.
Michael Snaer scored 16 points, including four straight free throws in the final 20 seconds, when Florida State repelled a late Virginia rally.
Singleton, last year's Atlantic Coast Conference defensive player of the year, already had 11 points when he was hurt 10 minutes into the game. He scored Florida State's first nine points before Xavier Gibson's put-back with 11:36 left in the half.
Florida State (18-7, 8-3 ACC) led 34-23 at halftime on its way to a second ACC win in less than 48 hours and fifth straight over the Cavaliers. The Seminoles were coming off a 72-63 win Thursday night at Georgia Tech.
Virginia (12-12, 3-7 ACC) fought back from a 16-point deficit in the second half and pulled to within 56-53 with 1:11 left on Joe Harris' short running jumper.
But Bernard James' baby hook with 37 seconds left provided Florida State a bit of breathing room and Snaer took care of the rest with his free-throw shooting.
Sammy Zeglinsky scored 19 points and Harris 17 for Virginia, which lost for the fourth time in five games. The two Cavalier snipers combined to make 9 of 20 tries from 3-point range.
But aside from Harris and Zeglinsky, the Cavaliers shot only 20 percent (6 for 30) and were beaten on the boards 40-29.
Snaer and James grabbed eight rebounds apiece for the Seminoles, who shot 44.7 percent and the 6-10 James blocked five shots.
The Seminoles, who are after their third straight 20-win season and third consecutive year with 10 wins in the ACC, tightened their grip on third place. The top four regular-season finishers earn opening-round byes in next month's conference tournament at Greensboro, N.C.