It's that time of year when "bracketology" becomes a meaningful exercise, and that gave urgency to St. John's Big East matchup with Xavier as two NCAA Tournament "bubble" teams fought to establish a foothold in the 68-team bracket Monday night at Madison Square Garden.

The Red Storm rallied from five points down with eight minutes left and hung tough down the stretch for a 58-57 victory when a buzzer-beating jump shot by the Musketeers' Myles Davis hit the front rim and bounced away harmlessly.

"It was a gut-check victory and another step in the right direction," St. John's coach Steve Lavin said.

The last bounce favored the Red Storm, which improved to 19-9 overall and 8-7 in Big East play with three regular-season games remaining, including the final home game against Georgetown Saturday at the Garden. One more win would give St. John's 20 and assure at least a .500 conference record to go with an excellent non-conference resume.

"With a win on Saturday, we'll have some breathing room," D'Angelo Harrison said. Recalling a 22-point loss to the Hoyas last week, Harrison added, "We just got blitzed by Georgetown. It will be Senior Night. I don't want to lose that game."

Harrison scored 15 of his 20 points in the second half after Xavier put together a 15-0 run for a 35-30 lead. But after two free throws by the Musketeers' Trevon Bluiett (17 points) with 25.2 seconds left, Harrison committed a turnover with 16 seconds left. That led to Davis' failed last-second shot.

"I just wanted to get a stop, and we did," Harrison said. "We make things really dramatic for no reason."

St. John's couldn't afford to lose to Xavier (18-11, 8-8) but was down 11-0. Lavin brought 6-10 center Chris Obekpa into the game, switched to a 2-3 zone, and the Red Storm went on a 20-2 run for a 22-15 lead.

The shot-blocking of Obekpa (4 blocks, 5 steals) and Sir'Dominic Pointer (19 points, 9 rebounds, 6 blocks, 4 steals) turned things around for St. John's in the first half.

"We played scared around the basket," Xavier coach Chris Mack said. "We missed layups, we got our shots blocked and then our guards became tentative and turned the ball over left and right."

The Musketeers managed to right the ship in the second half, but the combination of Pointer and Harrison was too much during an 11-4 surge that gave St. John's a 45-43 lead. Pointer had two blocks, an assist and a layup in that stretch, and Harrison scored the other nine points.

Mack called Pointer a "matchup nightmare," and Lavin said, "I can't imagine anyone in our league, let alone in the country, that influences a game at both ends in such dramatic fashion . . . He's like a tornado ripping up and down the court, a force of nature. He disrupts, discombobulates, unnerves opponents."

One or two more wins, and Pointer and the Red Storm should reserve a spot in the NCAA showcase. "As long as we keep playing our game," Pointer said, "our fate is in our own hands."