If Paul Hewitt had his way, his talented George Mason team would develop a killer instinct and avoid these repetitive harrowing finishes, the latest a 75-71 BracketBusters victory over Lamar in which the Patriots surrendered a 17-point lead Saturday.

Crippling lapses have “unfortunately become who we are,” he said. On the bright side, though, “we’ve become really good at executing down the stretch in close games,” Hewitt added with a nervous laugh.

Despite a 23-6 record, 11 wins in 12 games, a 15-1 home recordand a share of first place in the Colonial Athletic Association, the Patriots have enjoyed just one comfortable victory since December.

Four days after winning a buzzer-beating thriller against Virginia Commonwealth, the Patriots needed another clutch performance in the closing minutes to send 7,014 fans home happy.

Amid a flurry of George Mason turnovers and poor shooting choices, the Cardinals (17-10) used a 31-13 surge to go ahead by one. But Andre Cornelius, one of three seniors making their regular season farewell in Fairfax, restored George Mason’s lead for good with a three-pointer at the 2-minute 59-second mark.

Bryon Allen’s jumper extended the margin to four, but Lamar answered with two free throws and Anthony Miles missed a three-pointer with a minute left and a floater with nine seconds remaining. Ryan Pearson’s free throws with 6.4 seconds left secured the nervy victory.

“We seem to execute a whole lot better when the game is in the balance,” said Hewitt, whose team has won five straight by an average of five points.

The Patriots nearly lost despite shooting 68 percent in the first half and 57.1 overall, their second-best performance of the season. They nearly lost despite embarking on a 27-3 run en route to a 47-34 halftime lead — their highest-scoring half of the campaign — and making 7 of 14 three-pointers.

“We kind of were coasting,” Pearson said, “and thought the game was over.”

Far from it. With a 55-38 lead, the Patriots failed to score on 10 of their next 11 possessions. “I knew it was going to come back to get us,” Hewitt said.

They were still enjoying a 10-point lead with seven minutes left when their sloppiness returned, allowing the Cardinals to score in transition and make three three-pointers.

Lamar took the lead on Mike James’s steal and dunk with 3:17 left before Cornelius hit his third three-pointer.

“At times we get comfortable. Today we got a little comfortable and let our foot off the gas,” said sophomore guard Sherrod Wright (13 points). “They kept on fighting.”

Pearson, a senior forward, had 17 points to move into fifth place on George Mason’s career scoring list. He added 10 rebounds and four assists but committed six of his team’s 19 turnovers.

Lamar Coach Pat Knight, son of Hall of Famer Bob Knight, benched three starters for missing team functions Saturday morning. Forward Stan Brown, who had previous disciplinary issues, didn’t play at all. James, averaging 16.4 points, finished with 10 points and Miles had seven, less than half his average.

“The whole mind-frame of the team was kind of in the gutter the whole first half,” Knight said.

Patriots notes: The Patriots, who at 14-2 in league play are tied with Drexel for first place, will close the conference schedule by visiting Northeastern (8-8) on Wednesday and VCU (13-3) next Saturday. Drexel will host James Madison (4-12) and visit Old Dominion (12-4). . . .

Cornelius, Pearson and Mike Morrison were honored before the game. Retiring university President Alan G. Merten, a courtside regular at home games during his 16 years, was saluted during a timeout.