George Mason's Anali Okoloji (8 points) lands on top of U-Va.’s Joe Harris (game-high 19 points) while battling for a rebound Friday in Fairfax. (John McDonnell/The Washington Post)

With the shot clock winding down and the scored tied late in George Mason’s season opener Friday night against Virginia, Patriots guard Bryon Allen figured he better get off a shot to at least allow his big men a chance for an offensive rebound.

But as his desperation three-pointer, taken over the outstretched arms of Cavaliers guard Justin Anderson, sailed through the air and a sellout crowd of 9,840 at Patriot Center went quiet, Coach Paul Hewitt stood a few feet away thinking in more simple terms: “Please go in.”

The shot hit nothing but net and turned out to be the deciding basket as George Mason escaped with a thrilling 63-59 victory over the Cavaliers in a back-and-forth affair that felt more like a conference game than one played on the opening night of the college basketball season.

Allen finished with 13 points, seven of which came in the final 2 minutes 48 seconds of a game that featured 10 ties and 16 lead changes. He also dished out five assists to help the Patriots overcome a porous 8-of-19 showing from the free throw line.

“Once it got halfway there I knew it was going in. It was a big time shot I made,” Allen said of that defining sequence.

Senior Sherrod Wright led George Mason with 15 points and forward Johnny Williams added 11 on a night when the Patriots shot 54.3 percent from the field overall (68.4 percent in the second half) without guard Vaughn Gray and forward Erik Copes, who were both suspended this week for violating the school’s student-athlete rules. George Mason also committed just 10 turnovers, a notable achievement for a team that struggled to hold on to the ball a year ago.

Virginia, which played the entire game without a true point guard, got a game-high 19 points from junior Joe Harris and a career-high 11 points and seven rebounds from junior Akil Mitchell, but it wasn’t enough to avoid the program’s first season-opening loss in 15 years.

Virginia was without senior Jontel Evans and sophomore Malcolm Brogdon, who both remain sidelined because of offseason foot surgeries. In addition, redshirt freshman guard Teven Jones did not play because of a suspension for violating team rules. And the lack of a primary ballhandler showed at times.

The Cavaliers committed 12 turnovers, struggling at times to break George Mason’s full-court press. But Coach Tony Bennett lamented three consecutive giveaways after Virginia had taken a 50-46 lead with eight minutes remaining in regulation.

“When you’re in a game that close, a possession-by-possession game, I don’t know if our young guys understand the value of a possession on the defensive end or on the offensive end,” said Bennett, who started three freshmen Friday night. “Those were a couple of costly turnovers.”

After George Mason tied the score at 50, though, Harris responded with a clutch three-pointer and hit two free throws to keep the lead at four. But it would be nearly three minutes before the Cavaliers scored another point and the Patriots took advantage.

Williams hit a jumper, followed by a runner in the lane from Wright. Then Allen hit his miraculous three-pointer and swished two clinching free throws, and the Patriots emerged with a confidence-boosting victory over an ACC foe.

“It’s a great way to start the year,” Hewitt said. “By the end of the year, I think that win is gonna look even better.”