SAN JOSE, Calif. -- The path to this moment -- tied at 71, 50.4 seconds left, Xavier ball -- had been improbable enough already. Xavier, the West Region's No. 11 seed, had beaten 6-seed Maryland and then 3-seed Florida State in the Seminoles' Orlando backyard in a matter of three days just to get here. On this night alone, Xavier had played 2-seed Arizona more or less even for 30 minutes, recovered from the Wildcats' second-half scoring burst, and erased a 69-61 deficit with 3:45 to play. The Musketeers had held a high-powered Zona offense scoreless for the previous two minutes. They had sent win-probability algorithms into a "does not compute" tizzy.

Improbable had become the norm, in other words, by the time Xavier inbounded the ball, tied at 71, with 50.4 seconds to play. Somehow, the piece de resistance was still to come.

On the most important possession of Xavier's season, star guard Trevon Bluiett caught the ball at the top of the key ... and, without hesitation, floated a lob to forward Sean O'Mara, who scored the final two points of the game.

In the Musketeers' three NCAA tournament wins, Sean O'Mara is 11-of-13 from the field, a tidy 84.6 percent. Kyle Terada/USA TODAY Sports

Bluiett is Xavier's leading scorer, one of the hottest players in the tournament, and a gifted shot-maker under duress. O'Mara played 13.1 minutes per game this season and averaged 6.1 points.

And that was how the play was designed.

"It would have surprised me, definitely," said O'Mara, grinning, of how he would have responded if he'd been told even a couple of weeks ago that he would be the target of coach Chris Mack's timeout wizardry at a pivotal moment in the NCAA tournament. "We all thought the ball was going to Trey. And I think they thought the ball was going to Trey."

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There is no single, unifying explanation for Xavier's last six weeks, how a team that lost its starting point guard and six straight games in February is now one win away from the Final Four. Getting Bluiett healthy, installing tricky zone defenses, prior proof of success, the whole urn thing -- all of it belongs.

So, too, does O'Mara's metamorphosis -- from a little-used, all-but-forgotten reserve into, perhaps, Xavier's most vital frontcourt performer.

Xavier's coaches began the season with high hopes for the 6-foot-10 junior, who had always displayed a knack for the old-school art of playing with his back to the basket, but had struggled to add defending and rebounding to that equation. O'Mara averaged 17 minutes per game in the first seven games of the season, but quickly lost minutes to Rashid Gaston and Tyrique Jones. Mack stashed O'Mara on the bench. Short minutes led to compressed in-game pressure, which sapped O'Mara of his confidence on the offensive end.

"I think Sean had some in the beginning of the year, lost it, and then didn't play as well," Mack said. "And I give credit to Sean for being able to pull himself out of that rut and play his best basketball in the last month of the season."

The process of getting out of that rut came as it almost always does: individual work with coaches, tons of repetition, intensive self-study, constant encouragement.

"Seeing the ball go through the rim," O'Mara said. "Figuring out where I need to be. Seeing it all happen, over and over again, until it starts to manifest itself."

Even with all this work, no one could have expected O'Mara to manifest himself quite like this in the Musketeers' three NCAA tournament wins. In 63 combined minutes, O'Mara is 11-of-13 from the field, a tidy 84.6 percent. His 23 plays have resulted in 37 points, per Synergy scouting data, a 1.61 per-play average that as of Friday night was the highest of any player in the tournament who had played more than one game -- one spot higher than UCLA guard Lonzo Ball.

None of that production has come more than a few feet from the rim. O'Mara has been a revelation for those lamenting the lost art of the interior craft. His footwork is impeccable, he has moves and countermoves, he can finish over either shoulder, and he does his work early, sealing and pinning defenders before they realize they've already lost.

It's not all ground-bound grind, either: Against Maryland, O'Mara slipped a screen, dove to the rim, and sliced between two defenders for a dunk.

On Friday, Mack professed his belief that "good teams find a way to get the ball into the lane." O'Mara has given the Xavier staff a highly efficient means of achieving this goal.

He's also mixed in much better defense and some crucial work on the glass. After he put the Musketeers ahead Thursday night, O'Mara grabbed the key rebound on the other end before he was fouled. His miss on the subsequent one-and-one might be the only noteworthy mistake he's made all tournament.

O'Mara admitted that Saturday's ask against Gonzaga is the biggest, literally and figuratively, he has yet faced. Earning great position against 7-1 center Przemek Karnowski (and Zach Collins, for that matter) is not quite as easy as moving, well, basically anyone else.

"It'll be an interesting test to see if I can still get to my spot," O'Mara said.

If it seems improbable, well, it should. Then again, so does this: Xavier in the Elite Eight. And Sean O'Mara, go-to crunch-time scorer. As does this:

"We would not be in the position that we're in, playing for a Final Four, if it weren't for Sean," Mack said.

To paraphrase Muhammad Ali: Maybe improbable is nothing.