In his NHL debut Thursday, Kallgren made 10 saves on 11 shots playing 30:20 in relief of Petr Mrazek in a 5-4 overtime loss to the Arizona Coyotes.
"Erik looked really calm back there," Sandin said. "I'm super happy for him.
"I think we played a little bit harder. We really focused on our defensive game, took the defensive side of the puck first and then played off that. A lot of things in this game we got done that we need to keep doing every game, some things we still need to clean up, but overall we got the shutout and we needed that."
Stars captain Jamie Benn said they did not make it difficult enough on Kallgren.
"We wanted to put a lot of pucks on him, get a lot of shots, try and make his night difficult," Benn said. "I don't know if we did that. We did have a lot of shots, but we have got to find a way to put a few of those in."
Brothers Nicholas Robertson of the Maple Leafs and Jason Robertson of the Stars faced each other in the NHL for the first time. Nicholas, a forward, had two shots on goal in 11:09; Jason, also a forward, had three shots on goal and three hits in 17:38.
Jason Robertson made his NHL debut at Scotiabank Arena on Feb. 13, 2020, the last time Dallas played in Toronto.
NOTES: Kallgren became the 39th goalie with a shutout in his first NHL start. The most recent was Zach Fucale for the Washington Capitals on Nov. 11 in a 2-0 win at the Detroit Red Wings. Kallgren became the fourth goalie in Maple Leafs history to do it, joining Garret Sparks (3-0 against the Edmonton Oilers on Nov. 30, 2015), Al Rollins (8-0 against the Boston Bruins on March 25, 1950) and Benny Grant (3-0 against the Detroit Cougars on March 9, 1929). ... Tavares reached 20 goals for the 12th time in his 13 NHL seasons. Three active players have more 20-goal seasons: Alex Ovechkin (17), Sidney Crosby (14) and Patrick Kane (13). ... Marner's first assist, on Sandin's goal, was his 40th of the season, making him the first player in Maple Leafs history to begin his NHL career with six consecutive 40-assist seasons. ... Keefe got his 100th NHL regular-season win in his 163rd game. He is 100-46-17 in three seasons.