The course of Xavier’s season had taken a wrong turn along with Edmond Sumner’s left knee.

The standout sophomore point guard went down with a torn ACL on Jan. 29 against St. John’s at Madison Square Garden. The Musketeers then closed the regular season with six losses in 10 games to land on the bubble for the NCAA Tournament.

But two Big East Tournament games later at the Garden, that bubble doesn’t look as if it’s going to burst for them.

After beating 10th-seeded DePaul Wednesday night in the opening round, seventh-seeded Xavier upset second-seeded Butler, 62-57, Thursday night in the quarterfinals behind Trevon Bluiett’s 23 points, capped by the go-ahead jumper with 16.5 seconds left.

So the Musketeers moved up to 21-12 and on to the semis and a matchup Friday night against the winner of Thursday night’s late quarterfinal between No. 3 Providence and No. 6 Creighton.

“I don’t look at it as a relief,” coach Chris Mack said of the NCAA Tournament situation. “We have competitive guys. They understand what’s at stake . . . I still don’t know where we stand. I only care about the Big East Tournament right now.”

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Xavier led 57-56 when Butler’s Kethan Savage drove hard. He got clobbered by Malcolm Bernard and couldn’t stay in the game. The Musketeers were allowed to choose the free-throw shooter from the four on the floor. Mack picked Kamar Baldwin. He went 1-for-2 with to tie it with 38.6 seconds left.

After a timeout, Bluiett nailed a 14-footer for the 59-57 lead with 17 seconds left. Then Baldwin missed a three-pointer. Tyler Lewis grabbed the offensive rebound and missed a jumper.

J.P. Macura went 1-for-2 at the line for Xavier with 3.3 seconds remaining. The Bulldogs couldn’t corral the rebound on the miss. Tyrique Jones picked it up for the Musketeers and jammed it through before the buzzer.

So the Bulldogs, who were paced by Kelan Martin’s 15 points, still have never won a Big East Tournament game.

“We play pretty much a good team every year,” coach Chris Holtmann said. “We’re not ignoring the fact that we’re 0-4 . . . … We’re disappointed. We’re disappointed for our fans.”