The Golden Eagles led, 43-29, at halftime and stretched that to 56-39 on Mayo's three-pointer with 13:10 left. But Clark brought Georgetown back, making six of seven shots in the second half, when he scored 18 points.
With starters Sims and Thompson sitting with three fouls each in the second half, Georgetown went with a lineup of freshmen Jabril Trawick, Otto Porter, Greg Whittington and Mikael Hopkins, along with senior guard Clark. Something clicked, because the Hoyas starting chipping away at that big deficit.
Clark did most of the scoring, including a three-pointer and a three-point play. And when Sims went back in and made one of two free throws, then assisted on Porter's backdoor cut for a layup, suddenly Marquette's lead was down to 62-57 with a little more than 7 minutes remaining.
It helped that Marquette went cold for a stretch, going more than 7 1/2 minutes between field goals.
When Thompson swished a three, the Hoyas were down by only 66-64, and his fallaway baseline jumper tied it. After yet another Marquette turnover, Sims' layup put Georgetown ahead, 68-66, with a little more than 2 minutes to go. After the teams traded scores, the game was tied at 70-all when Thompson made his biggest shot of the game.
Johnson-Odom and Crowder both got late looks at potential tying threes, but both missed.
In other games *
At Providence, Brandon Triche had 16 points as No. 1 Syracuse (16-0, 3-0 Big East) beat the Friars, 87-73.
* At Kansas, Travis Releford had 16 points, leading the No. 14 Jayhawks (11-3, 1-0 Big 12) past 23rd-ranked Kansas State, 67-49. Rodney McGruder had 15 points for the Wildcats (11-2, 0-1).
* At Murray State, Donte Poole had 22 points and Isaiah Canaan added 16 - including the 1,000th of his career - and the No. 19 Racers (15-0, 3-0 Ohio Valley) beat Eastern Kentucky, 76-67.