There wasn’t much that separated the Merrimack and Nashua South high school boys basketball teams Tuesday night, but what did made a big difference.

Down by 14 points early in the fourth quarter, South found a way to climb back into the game. But, from there when the Panthers needed baskets, they couldn’t get them.

At the other end, Merrimack was able to execute a couple of plays to maintain the lead and the Tomahawks held on for a 65-59 victory to remain undefeated (6-0) in Division I action.

“That’s what they do,” Merrimack coach Tim Goodridge said of South’s comeback. “That press is impressive. They’ve got a lot of quick guys and (Trevor) Knight is as quick as anything. I give my kids credit for breaking it. They got a few things out of it and there were a couple of trying times, but overall, I thought we handled it well.”

Eric Gendron led Merrimack with 16 points, including the thousandth point of his career, while Shayne Bourque chipped in with 12 points and Austin Franzen had nine, including an acrobatic layup in the final 90 seconds that helped close out the win.

“I think (Gendron) shared the ball really well and I think that’s what made us a better basketball team,” Goodridge said. “We got a lot of contributions from a lot of kids. The nights that Eric scores 35 and we don’t get a lot from anybody else … what we need to do is win games like we did (Tuesday).”

South (3-2) got a game-high 22 points from Yordy Tavarez, and Mike Osgood was also in double figures with 11 points, but the Panthers struggled at times against Merrimack’s defense, including a five-plus minute stretch in the third quarter with just two points.

The Panthers got out to a quick start, jumping ahead 7-2 before the Tomahawks switched up their defense to slow down the quicker Panthers. The switch worked and Merrimack took a 16-15 lead into the second.

The teams went back and forth over the first few possessions of the second, but a 10-3 run by Merrimack put the Tomahawks up seven with 2:32 to play. That basket by Gendron put the senior over a thousand, making him just the seventh boys basketball player in school history to reach the milestone.

The lead ballooned to eight, 33-25, on a 3-pointer by Mike Conlin with 1:10 to play, but South hung around.

Merrimack upped its lead to 10 at the end of the third quarter and went up 55-41 with 6:07 to play before South regrouped.

The Panthers went on a 15-2 run, cutting the lead to one on two free throws by Trevor Knight with 3:01 left to play. But from there, South struggled and Merrimack executed on its end.