Washington, DC – Henry Sims had 13 points, nine rebounds and 45, on Saturday.
Otto Porter added 12 points and Jason Clark finished with 11 for the Hoyas (18-4, 8-3 Big East), who won for the fifth time in six games and improved to 12-1 at home this season. Markel Starks and Jabril Trawick chipped in 10 apiece.
"From day one, we've stressed that if we defend and rebound everything else will be OK," said Georgetown coach John Thompson III.
Augustus Gilchrist scored a game-high 15 points for the Bulls (13-10, 6-4). They were coming off an 81-78 win over Providence, but were held to their third-lowest point total of the season.
Saturday's game featured the top-two scoring defenses in the Big East and the action was indicative of such a matchup.
The Bulls, who entered with the conference's best scoring defense, were up 5-4 before they went over 10 minutes without a field goal. The Hoyas took advantage, scoring 14 straight behind four points from both Sims and Clark.
Gilchrist broke the drought, hitting a top-of-the-key trey to make it 18-8 with three minutes left in the half and Anthony Collins had the Bulls down eight, 23-15, at the break with a buzzer-beating layup.
The Hoyas, who held Connecticut to 44 points in a win on Wednesday, continued to ratchet up the pressure in the second half. They opened with a 6-0 burst, as Hollis Thompson, Starks and Sims all scored to stretch the advantage to double-digits.
Later, an 8-0 run, highlighted by a trey from Starks and capped by a pair of free throws by Sims, had Georgetown up 20, 39-19, with 13 1/2 minutes remaining.
South Florida didn't threaten the rest of the way and Aaron Bowen sealed the final result with an alley-oop slam at the buzzer for the Hoyas, who will take on No. 2 Syracuse on Wednesday.
"We just got real frustrated offensively," said South Florida coach Stan Heath. "The more we couldn't score the more we got frustrated and all of a sudden the avalanche opened up."
South Florida entered Saturday allowing 59.0 points per game, while Georgetown entered allowing 59.2 ppg...The Hoyas have held 12 teams, including five Big East opponents, to under 60 points this season...Georgetown leads the all-time series, 8-3.