BOSTON -- The Vegas Golden Knights made former Boston coach Bruce Cassidy's return a success, as Reilly Smith scored in the fifth round of the shootout to beat the Bruins 4-3 and end their NHL record for home victories to open a season at 14 games Monday night.

The 57-year-old Cassidy was fired by Boston following 5½ seasons in June after the Bruins were eliminated by Carolina in the opening round of the playoffs. Eight days after he was let go, he was hired by Vegas.

In a matchup of two of the league's top three teams, Western Conference-leading Vegas opened a 3-0 lead early in the second period on two goals by Paul Cotter and the other by Jonathan Marchessault. It was the first time the Bruins allowed the opening three goals of a game this season.

But the Bruins started their comeback when Brad Marchand and David Pastrnak scored just over six minutes apart late in the period. They tied it on Taylor Hall's power-play goal 3:08 into the third when he spun in front and slipped a shot from the slot past goalie Logan Thompson.

Smith had the only score in the shootout, slipping a forehand shot past Jeremy Swayman.

It was Vegas' 14th road win of season, tied with the Dallas Stars for most in the West.

Cassidy took over as Boston's interim coach Feb. 7, 2016, before getting the top job that April. His teams made the playoffs all six seasons, including a trip to the 2019 Stanley Cup Final when they lost the seventh game at home against St. Louis.

The Bruins played a video montage of Cassidy on the Jumbotron late in the opening period that ended with a picture of him and said: "Welcome back, Bruce.'' The crowd gave him an ovation and he waved thanking them.

Cassidy knows what it sounds like in TD Garden with The Standells' song "Dirty Water'' blaring after Bruins' wins.

"I'm glad I didn't hear it tonight," he said, smiling. "The streak is irrelevant to me. It's nice to come in and play well.''

The Bruins' home-opening streak broke the record of 11 that was set by the 1963-64 Chicago Blackhawks and equaled by the Florida Panthers last season.

Boston lost for just the second time in 12 games.

"This locker room sticks together, and we knew we were going to do something special tonight,'' Swayman said. "It [stinks] losing, but we're going to make sure we fix the problems.''

Before the shootout, Thompson made 40 saves. Boston's backup netminder Swayman had 21.

"This city meant a lot to him, and he was fired up ready to go,'' Thompson said of Cassidy. "We went out there and tried to get him two points tonight.''

Cotter collected William Karlsson's pass inside the left circle and unloaded a wrister under the crossbar 1:36 into the game. Marchessault stole Pastrnak's attempted clearing pass, broke in alone and tucked in his own rebound to make it 2-0.

Cotter's second goal came 51 seconds into the second period when he slipped a wrister past Swayman's glove.

"We couldn't get it done early, before the shootout. We had chances,'' Pastrnak said. "It's a tough one to swallow.''

Vegas star forward Jack Eichel missed the game with a lower-body injury.

Information from The Associated Press was used in this report.