Pietrangelo scored into an empty net with a 1:00 left to make it 4-2. It was his NHL career high 16th goal of the season.
"I've been trying to shoot more this year, so the more you shoot, maybe the more you score," Pietrangelo said.
Stolarz was recalled from San Diego of the American Hockey League on Monday. He had not played in the NHL since April 4, 2019, when he made 24 saves for the Edmonton Oilers in a 3-2 loss to the San Jose Sharks.
"He's had an excellent season," Ducks coach Dallas Eakins said. "To come in and play the way he did against the Stanley Cup champions, I think [Stolarz] should be feeling real well about that."
Bouwmeester collapsed on the bench Feb. 11 and was revived with a defibrillator. He had an implantable cardioverter defibrillator (ICD) procedure Feb. 14, and the Blues placed him on long-term injured reserve four days later.