The 22-year-old rookie had two assists in a 3-2 overtime loss while playing with a microfracture and ligament damage in his right wrist after he was slashed by Canadiens defenseman P.K. Subban in Game 1 on Wednesday.
"[Stone's] a character guy for us," MacArthur said. "He's going to battle through it and do what he has to do. That's all you can ask of a teammate. For him to step in there as a young guy, it's gritty of him. Hats off to him.
"It's that time of year when you need guys to step up and be a man, and that's what he is. It's great having him in there and it makes you want to go that much harder when he's out there."
Montreal leads the best-of-7 series 2-0. Game 3 will be at Canadian Tire Centre on Sunday (7 p.m. ET; NBCSN, CBC, TVA Sports).