Georgetown paid dearly for its mistakes on offense, allowing Marquette to spend all afternoon scoring and drawing fouls in transition.
Now the Hoyas will have to play an extra day in the Big East tournament.
Otto Porter and Hollis Thompson scored 19 points each but that wasn't enough for the Hoyas, who lost 83-69 at No. 8 Marquette on Saturday — and lost out on the chance to secure a double-bye in the conference tournament.
"We came in here with the opportunity to control where we finished," Georgetown coach John Thompson III said. "We didn't do what we were supposed to do, so you end up playing on Wednesday instead of Thursday. That's a lesson that's got to be learned."
Jae Crowder had 26 points and 14 rebounds while Darius Johnson-Odom added 17 points for the Golden Eagles, (25-6, 14-4). Marquette was 33 of 45 from the free-throw line.
The Golden Eagles forced 15 Georgetown turnovers, outscored the Hoyas 24-8 in points off turnovers and held Jason Clark to 11 points on 4-of-14 shooting.
Clark said all those transition baskets were the result of offensive mistakes by Georgetown (22-7, 12-6).
"They are a good transition team and they were able to get out and run and score baskets," Clark said.
With the victory, Marquette finished the season undefeated at home in Big East play. The Golden Eagles rebounded well from a disappointing 72-61 loss at Cincinnati on Wednesday, where they shot 34 percent from the field and tied a season high with 17 turnovers.
Forward Davante Gardner returned for the Golden Eagles, checking in at the 11:17 mark in the first half.
Gardner had been out since injuring his left knee in Marquette's victory at Villanova on Jan. 28, missing eight games — a significant loss for an already undersized team.
The 6-8, 290-pound Gardner had six points and eight rebounds in nine minutes in the first half. But he had trouble moving at times and limped noticeably to the bench when he was taken out of the game just before halftime.
Gardner played only six minutes in the second half, finishing with eight points and eight rebounds.
Leading 39-29 at halftime, Marquette opened the second half on a 9-2 run to take control of the game.
With Marquette pressing on defense, Crowder came up with a steal near midcourt, then launched an alley-oop pass to Jamil Wilson, who slammed it home to give the Golden Eagles a 48-31 lead with 17:55 left.
Wilson was assessed a technical foul for hanging on the rim, but momentum clearly was in Marquette's favor.
The Golden Eagles knew a double-digit lead wasn't necessarily safe against the Hoyas. Georgetown beat Marquette 73-70 Jan. 4, with Thompson hitting a 3-pointer with 24 seconds left. The Golden Eagles held 17-point lead in the second half of that game — and were determined not to squander another one.
A Georgetown spurt would cut Marquette's lead to 51-43 with 14:31 left. Georgetown's Henry Sims then fouled out with 9:33 left, leaving the game with five points and nine rebounds.
With Marquette nursing a nine-point lead, Crowder converted a three-point play — then came up with a steal and a fast-break layup, giving the Golden Eagles a 67-53 lead with 6:33 left.
"He is just all over the place," Porter said of Crowder. "We just had lack of communication knowing where he is at all times and rebounding."
The Hoyas again cut the lead to nine with a shot by Porter and a three-point play by Mikael Hopkins, but Crowder scored on a putback and was fouled. Crowder missed the free throw, but Marquette led by 11 with just under four minutes left.