Chaz Williams of Massachusetts drives past GW’s Joe McDonald in the Atlantic 10 tournament at Barclays Center in New York. (Mike Lawrie/GETTY IMAGES)

The George Washington men’s basketball team had every opportunity to extend its season Thursday night, even as the 11th seed in the Atlantic 10 tournament. The Colonials held a five-point lead over No. 6 seed Massachusetts with less than four minutes to play at Barclays Center.

Then what had the makings of another benchmark victory in Coach Mike Lonergan’s second year of rebuilding unraveled quickly, leaving the Colonials on the short end of a 77-72 contest.

Junior Chaz Williams, a first-team all-conference point guard, converted a layup with 1 minute 18 seconds left in regulation that gave the Minutemen the lead for good, and he followed shortly thereafter with another layup for a 75-72 advantage. Lonergan called timeout after that basket, and with 33 seconds to play, George Washington senior forward Isaiah Armwood missed a short jumper, but teammate Patricio Garino collected the rebound.

As Garino moved to the left wing, Williams swooped in from behind for the steal, and Colonials senior guard Bryan Bynes had to foul Trey Davis, whose two free throws produced the game’s final points.

“Proud of our effort,” Lonergan said “Feel bad for our guys. I thought they did a real good job. The effort was there tonight, and a four-point lead in the last few minutes. I thought we were doing a great job on Williams, and he just sort of took over with his speed. I think we had some tired legs and just didn’t get back on defense.”

George Washington (13-17), which lost five of its final six, stumbled in the first round of the Atlantic 10 tournament for the fourth straight season in large part because of 18 turnovers and 38 percent shooting, including 0 for 8 from three-point range. The Colonials were able to take the outcome down to the wire, though, because of a 50-32 rebounding margin and making 20 of 24 foul shots (83 percent).

Freshman forward Kevin Larsen led George Washington with a game-high 17 points and had seven rebounds, and Armwood chipped in 16 points and a game-high 13 rebounds. Senior Lasan Kromah scored 11 points and freshman Joe McDonald added 10.

“We got the lead late, but toward the end they made some big plays,” McDonald said. “They started bringing some pressure, and we made some costly turnovers, and you’ve got to give them a lot of credit.”

In a game in which neither team led by more than five points and included 19 lead changes and 14 ties, the Colonials appeared poised for the upset when they followed a 6-0 run with another burst that provided a 66-61 lead with 3 minutes 53 seconds to play after consecutive bank shots from Larsen.

But Massachusetts (20-10) countered with a pair of three-pointers from Davis, a freshman guard, sandwiched around two Larsen free throws. Minutemen Coach Derek Kellogg called timeout after the second three-pointer, and Massachusetts got the ball back when Larsen was called for taveling in the back court.

Williams made a driving layup off the glass moments later for a 69-68 lead, and the lead changed thereafter four times until the Minutemen’s closing kick that avenged a 79-76 loss to George Washington on Jan. 19 in Amherst, Mass.

“We got moving, which we really tried to do all game long,” Kellogg said. “I thought out guys did a better on the press. We had a lot more energy, and we made some shots. We had to make some shots because we weren’t rebounding the ball quite as well as I would have liked or anticipated after a week of practice.”