Pastrnak completed the hat trick with a one-timer on a 5-on-3 power play at 16:45 to make it 3-2, and Rask saved all 12 shots he faced in the third period.
"Talking to him after, there were no issues with the (hip) surgery," Cassidy said. "A little sore in spots, but I think that's just from not playing in a while. He said his conditioning was pretty good."
Rask signed a one-year contract with an NHL salary cap charge of $1 million on Tuesday. He had not played since Game 6 of the 2021 Eastern Conference Second Round against the New York Islanders and had surgery in July to repair a torn labrum.
"Even though it wasn't killing me every game last year, it's always in the back of my head that certain movements were limited," Rask said. "It's great to feel that I have the ability to move both ways."
NOTES: Rask is 8-3-0 in his season debuts. Only Marc-Andre Fleury (10-6-0) has more wins in season debuts among active goalies. … Flyers forward Claude Giroux had three shots in 20:25 of ice time after missing three games in NHL COVID-19 protocol. … Bruins defenseman
Matt Grzelcyk
was placed in NHL COVID-19 protocol prior to the game. He scored six points (one goal, five assists) in the previous two games. … Pastrnak has 11 regular-season hat tricks, three against Philadelphia (Feb. 3 and Feb. 21, 2021). … Marchand and Pastrnak became the fifth Bruins teammates to each score a hat trick on consecutive days, joining Peter McNab and Barry Pederson (April 3-4, 1982), Wayne Carleton and Phil Esposito (April 3-4, 1971), Bobby Orr and Esposito (Dec. 14-15, 1968), and Bill Cowley and Herb Cain (March 4-5, 1944).