George Mason will begin its inaugural Atlantic 10 campaign next week by facing Virginia Commonwealth’s torrent of pressure, but if the lack of composure late in Thursday’s game against two-win Penn was any indication, the Patriots are in for a rude conference welcome.

In a blizzard of mistakes and missed free throws, they allowed an 11-point lead to almost entirely evaporate before surviving a potential tying shot for an 80-77 victory at Patriot Center.

“We have to take care of the ball and be aware of the situation,” senior guard Bryon Allen said.

Allen scored a career-high 24 points – he didn’t miss from the field or line until midway through the second half – and sophomore guard Patrick Holloway continued his searing shooting with 18 as the Patriots (7-6) won their second straight since losing six of seven.

Mason will close the non-conference slate Saturday at Old Dominion, then venture into the A-10 with several early tests.

The Patriots have endured a trying few months: Starter Erik Copes was suspended six games for off-court issues; starter Jonathan Arledge, sidelined with a back injury, is seeking to transfer; the veteran squad began a four-game rut by squandering a 17-point lead at home against South Florida; and Anali Okoloji was suspended one game for stepping on an opponent.

In their first home appearance in more than a month, Mason continued to stumble. The Quakers (2-9) shot 63 percent in the first half and breezed to the basket as if they were conducting a pregame layup drill.

After one particularly porous effort, Coach Paul Hewitt hollered to the rafters.

“I was disappointed in the first half,” he said, despite his team trailing by just two at intermission. “I told them, ‘You guys beat up more on each other than the opponent.’ In the second half, we started to match their physical play.”

Freshman Jalen Jenkins (10 points, six rebounds) sparked a late first-half burst and Allen began the second-half rally with a three-point play and three-point shot.

The Patriots went ahead to stay on Holloway’s three-pointer with about 13 minutes left. Their rejuvenated defense limited the Quakers to one field goal over 61 / 2 minutes, and Holloway and Allen stretched the lead.

All finally seemed well. Up by 11 with two-plus minutes left, however, the Patriots proceeded to make 3 of 8 free throws. If not for a missed breakaway with 47 seconds left, the Quakers might have pulled out a miraculous victory.

Tony Hicks’s three-pointer cut the deficit to three with 12 seconds left, and after Mason’s Johnny Williams missed two free throws a second later, Hicks’s long attempt smacked the backboard.

Hicks had 23 points and six assists.

Holloway finished one point shy of his career high. He averaged 15.3 points in three games at the recent Hawaii tournament, making 12 of 20 three-pointers. He was 4 of 7 against Penn.

“The main thing is I’m getting a lot of shots up,” the former All-Met from Paul VI said. “My teammates have trusted me. Even when I was in a slump at the beginning of the year, they still passed me the ball. That gives me confidence and allows me to keep making shots.”

With conference play looming, the Patriots will have to do more than make shots. Particularly in the critical stages.

“All good teams go through bad stretches of the season,” Allen said. “We know we have a good team and we know coming into the A-10 it’s going to be a tough conference – a lot tougher than the CAA. We just have to keep moving forward.”