Senior Austin Knight (2) of the ConVal boys basketball team drives to the hoop during the Cougars’ game against Souhegan on Thursday in Peterborough.

PETERBOROUGH — It felt like a showdown between two undefeated teams at the Cougar Cave on Thursday night.

With both student sections thundering all night long, the Souhegan boys basketball team took down ConVal, 45-42, in comeback fashion to stay unbeaten and hand the Cougars their first loss of the year.

ConVal (7-1) built up a nine-point lead at halftime, 29-20, but went ice cold in the second half, missing their first nine shots in the third quarter. The Cougars only scored three points in the third.

“It’s the opposite of what we talked about coming out of the half,” said ConVal coach Jason Starr. “We talked about coming out really strong and try to either put the game away or go on a little run. We did the opposite and [Souhegan] came out on a run.”

Souhegan (8-0) hit just about everything in the third quarter and went on a 20-3 run to start the second half. The Sabers led 34-32 by the end of the third quarter, then pulled ahead, 40-32, early in the fourth.

Souhegan used its size — highlighted by 6-foot-8 center Johnny McBride — to shut down the ConVal offense in the second half, holding the Cougars to 1-for-13 shooting in the third quarter and 3-for-14 in the fourth.

Compare that to ConVal’s offense in the first half: 5-for-10 in the first frame, 4-for-11 in the second quarter.

“They did a pretty good job of slowing us down,” Starr said. “They had possessions that were a minute long. That was good on their part. I thought we did a good job in the first half running and getting it going, but second half we were just selfish, that’s what I felt.”

ConVal also got to the free throw line five times in the first half, going 8-for-9 from the charity stripe. The Cougars only shot four foul shots in the second half.

Souhegan led off the night with four quick points, before Christian Buffum (10 points) scored five points to spark the offense and the ConVal crowd.

The Cougars built off of that quick first-quarter run, eventually pulling ahead 17-10 with five minutes to go in the half before Malachi Page (11 points) hit a three-pointer to extend the lead to 10.

Things got a little chippy at the tail end of the first half when Buffum was called for a foul on Souhegan’s Johnny McBride (14 points). With both players down on the court, Buffum stepped over McBride as they were getting up, which McBride didn’t seem to appreciate.

McBride was assessed a technical foul for retaliating against Buffum, and Austin Knight (19 points) hit both free throws. The Cougars went to the locker room up 29-20 with both fan bases riled up after the short confrontation.

Souhegan came out of the locker room hot, while ConVal came out cold, as the Sabers outscored the Cougars, 14-3, in the third quarter, which turned out to be the decider.

“On offense, I think we were playing a little too selfish,” Starr said. “We do a good job of sharing the ball and playing free and wide open and looking to attack the basket. And I felt like in that second half maybe we were just trying to get our own points and not worry about the team ball. That kind of got away from us.”

“[Souhegan’s] game plan coming in was to slow us down,” Knight said. “They just tried to slow us down and take advantage. They were bigger than us in size, so they were trying to take advantage when they could and they capitalized on it.”

Despite the lack of offense in the second half, ConVal was never out of it until the very end, down nine with 30 seconds to play.

Buffum hit a three-pointer to cut the deficit to six with 20 seconds to play, and Knight hit a three-pointer at the buzzer, but the shots fell too late. The Souhegan student section had already started their “un-de-feat-ed” chant as the clock hit zero.

“We just need to put it behind us,” Knight said. “It’s just one game, we’re still a good team. Can’t dwell on this loss.”

“It’s onto the next game,” Starr said. “They weren’t hooting and hollering and playing music like they normally are after the game, but I think they’re focused. We have a lot of seniors so we’re a mature group. Hopefully we can get it together and have a good weekend.”

There’s little doubt that these two teams will see each other again down the road, and the stakes will be quite a bit higher in that potential postseason matchup.

“We’re definitely looking forward to seeing that team again,” Knight said. “We definitely can play way better than we did tonight.”

Before then, the Cougars kick off the second half of the regular season with four games over the next six days, starting with Milford (3-6) on Saturday in Peterborough, then Hanover (2-6) on Sunday in Hanover.

“There’s no time to feel sorry for ourselves and sulk,” Starr said. “We’ll get right back at it and keep working hard.”

Chris Detwiler can be reached at 352-1234, extension 1411, or cdetwiler@keenesentinel.com. Follow him on Twitter @Chris_Detwiler.