Floyd was given two technical fouls and ejected with 47.9 seconds remaining for arguing an offensive foul called against Daniel Hackett with ASU leading 57-51.
Glasser made six free throws in the final 47.9 seconds to wrap up the win and give Arizona State its first back-to-back 20-win seasons since 1980-81.
Freshman DeMar DeRozan scored 16 points to lead USC, which has lost three straight for the first time this season.
James Harden, the Pac-10's leading scorer at 21.6 per game, had 13 points for ASU, while being mainly covered by Hackett. Harden attempted only six field goals but made five.
Jamelle McMillan had 11 points, hitting three 3-pointersfor Arizona State.
ASU led 52-40 with 5:26 remaining after a 14-2 run keyed by two 3s from McMillan, the son of Portland Trail Blazers coach Nate McMillan, who attended the game during the NBA All-Star break.
Hackett, Taj Gibson and Dwight Lewis had 11 points for USC.
ASU did not commit a turnover in the first half and had only four turnovers after committing 17 in the first meeting with USC, a 61-49 Trojans' victory, and 17 against UCLA in a 74-67 victory over the Bruins on Thursday.
ASU went on a 21-11 run in the first half sparked by Pendergraph and Glasser.
Pendergraph had 10 points, seven rebounds and three assists in the first half, and he made two slam dunks and a layup as ASU took a 23-18 lead.
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