AUGUSTA — Serge Nyirikamba’s fourth foul was just the break Monmouth was looking for late in Monday’s Western Class C quarterfinal.

Relegated to the bench with five minutes left, Waynflete’s 6-foot-3 senior forward wouldn’t be able to perform his low-post surgery for a while, or intimidate the Mustangs at the other end.

Nyirikamba had barely settled into his seat when Monmouth’s Huter Richardson drilled a 3-pointer to cut a 10-point deficit down to seven. The Mustangs seemed to have the momentum it needed to pull off a comeback.

But a couple of turnovers and Nyirikamba’s co-captain, Henry Cleaves, quickly shifted that momentum back to the third-seeded Flyers, and for the second consecutive year, they ended the Mustangs’ season at the Augusta Civic Center.

Nyirikamba tallied 26 points, 16 rebounds and four blocks and Cleaves scored nine of his 13 points in the fourth quarter as Waynflete held off No. 6 Monmouth, 66-51.

The Flyers (16-2) advance to Thursday night’s semifinals, where they will face No. 10 Hall-Dale.  Monmouth ends its season at 12-8.

Nyirikamba left the game with his team up by 10. He returned a little less than three minutes later with the same cushion.

“We had a comfortable lead so I wasn’t really worried,” Nyirikamba said. “I was just focusing on helping my teammates out while I was on the bench, so I wasn’t too worried.”

“I thought momentum was on our side. I thought we could get to the rim (with Nyrikamba out),” Monmouth coach Lucas Turner said. “He’s the guy that was killing us.  But they went to the free throw line a couple of times and we turn it over and that made it 10 or 12 again real quick.”

Cleaves scored the last eight points in a 10-0 run as the Flyers pulled away.

Marcques Houston led Monmouth with 17 points. Brett Wilson added 12 on four 3-pointers for the Mustangs, who lost to Waynflete in last year’s quarterfinals by 31 points.

“This year, they seemed more comfortable with the ball,” Nyirikamba said, “and their shots were falling.”

Not as well as Waynflete’s shots were falling. The Flyers shot 61 percent from the floor, compared to Monmouth’s 36 percent.

The Mustangs elected to play Nyirikamba one-on-one in the first half and he torched them for 15 points.

“They have three guards that can get to the rim and shoot,” Turner said. “Wherever you double from, if you choose to double, you’re doubling off somebody that can shoot or get to the rim.”

Houston finished the first half strong to keep the Mustangs close at halftime, 31-27. Monmouth started to double-team Nyirikamba in the third quarter and pulled within 35-33 on a Brandon Goff putback.

The Flyers responded with an 11-3 run. Nyirikamba scored nine of those points, including a pull-up jumper and a pretty scoop shot in transition to make it 48-36 late in the third.

“He’s got great pivot moves, but he’s so long,” Turner said. “He is so tough to defend, especially when we started doubling him. He can read where that double is coming from. He spins the other way and he’s very patient with the ball.”

“I’ll take an escape dribble and then get it out to an open shooter, or someone is going to get open fast because I’m being doubled,” Nyirikamba said.