St. John’s was on the comeback trail Sunday night against 24th-ranked Xavier, having erased all but two points of a 15-point deficit. The crowd of 8,723 at the Garden finally had come to life, and during a break in play, Marcus LoVett raised both hands in the air, exhorting the fans to cheer louder.

With the Musketeers trying to hold on after losing star point guard Edmond Sumner to an unsightly knee injury, the Red Storm was on the cusp of an upset. It just couldn’t get to the summit. Unable to overcome the combination of a bad three-point shooting performance and Xa vier’s relentless offensive rebounding, St. John’s ultimately fell, 82-77, in Big East action.

St. John’s (10-13, 4-6) failed to build on an impressive road win over Providence and reach .500 in conference play. It shot 5-for-23 from three-point range and was outrebounded 45-26, including 17 offensive rebounds by Xavier.

“That was a winnable game,” LoVett said.

Asked if he thought his team should have won, Chris Mullin said, “Should have? I don’t know. Definitely could have.”

When Xavier’s Trevon Bluiett pulled up for a three-pointer in transition, the Musketeers (15-6, 5-3) took a 59-44 lead with 9:52 to play. They went ahead 68-56 with 6:01 left when Sumner scored on a drive and came down awkwardly, his left knee bending in the wrong direction (Quentin Goodin replaced him and converted the three-point play). Still, St. John’s twice got to within two despite missing four free throws in the run.

advertisement | advertise on newsday

LoVett made one of two free throws to make it 68-66 before Shamorie Ponds (23 points) committed a backcourt foul on the press to give Goodin two free throws. Then Ponds was fouled on a drive and made two free throws to make it 70-68. Xavier answered with a one-hander by RaShid Gaston and a bank shot by Bluiett around LoVett’s turnover for a 74-68 lead.

LoVett and Bashir Ahmed had 11 each for St. John’s. Bluiett had 21 points and Sumner 17 with seven assists for Xavier.

Musketeers coach Chris Mack said of Sumner’s knee, “It obviously didn’t look good. We’ll find out Monday [after] an MRI. Keep him in your prayers.”

Mullin felt that “most nights we probably win, but we make some threes.”

Still he felt optimism in the face of defeat.

“I’ll focus on the comeback. We got down 15 and we didn’t get discouraged,” he said. “ . . . But ultimately some of those rebounds came back to haunt us. Believe it or not, I’m kind of optimistic [because] usually we make some threes and we were 5-for-23 from the three=point line. And then the 17 offensive rebounds was probably the difference.”