Wins by Duke and No. 13 North Carolina Wednesday left those two teams tied for the lead in the Atlantic Coast Conference with one game to play.
That game will send the Tar Heels and Blue Devils against each other Saturday on North Carolina's home floor. North Carolina put the pressure on Duke earlier in the evening with a 72-70 victory at Florida State.
Duke had only a two-point lead near the midway point of the second half before the Blue Devils went on a decisive 10-2 run over a span of more than 6 minutes.
Smith scored 21 points and handed out seven assists. Singler had 18 points to go with 11 rebounds.
Duke (27-3, 13-2 ACC) bounced back from a loss at Virginia Tech last Saturday.
Demontez Stitt led Clemson (19-10, 8-7) with 18 points.