Flintridge Prep won its third game in as many attempts during the Maranatha summer league, but first with Cartwright, who missed the opening two contests with a concussion.
The guard turned in an all-around solid effort with 12 points, 11 assists, five rebounds and two steals and was tested at the six-minute mark in the fourth when he was shoved to the floor on a hard foul.
"I wasn't worried at all. In fact, I really don't know what happened," Cartwright said. "I thought someone stuck their leg out. It was an interesting play."
Cartwright and senior teammate Jedrick Eugenio, who scored a game-high 22 points, helped ice the game just as it became interesting.
Glendale trailed by as many as 25 points midway through the third quarter, but hacked its deficit to 61-55 with 3:35 left in the game after consecutive three-pointers from Vahe Aristakessian and Stephan Arakelyan.
Cartwright answered by slicing through the lane and feeding Eugenio, who missed a 10-footer, but was fouled by Arthur Trzyan.
Eugenio sank both free throws and then drained a three-pointer on Flintridge Prep's next trip down court, thanks to an assist from Harrison Jung, in putting the Rebels up, 66-55, and sealing the contest.
"Flintridge Prep is a very good team and we just allowed them to penetrate too much too often," Glendale Coach Steve Snodgrass said. "I was pleased with what we were able to do on offense, but we're going to have to improve on defense, especially when we see teams with strong guards like Prep."
It wasn't just the Rebels' guard play that was effective.
For a third straight contest, Flintridge Prep proved more physical than its opponent as the forward combo of Kareem Ismail and Chad Cosse combined for 29 points, 15 rebounds and three blocks.
That was compared to five points and 10 rebounds from Nitros' post players.
Despite the score, there were some bright spots for Glendale, including the play of guards Rene Saavedra and Aristakessian, who both shared the jersey No. 15.
The duo combined for 29 points and 16 rebounds and scored eight of the final 10 points in the third quarter to rally Glendale to within 52-42 at the end of the third quarter.
"We certainly did better as this game went on," Snodgrass said. "[Cartwright] is certainly a talent, but I thought Arada Zakarian (13 points) played him well and has played well against some very good guards this summer. If we aren't as passive defensively as we were today, this could have certainly been a different score."
Flintridge Prep continues play Thursday at Maranatha at 4 p.m. versus Northridge, while Glendale entertains small-school force San Gabriel Academy at 5:10 p.m.