The Flyers scored five more times in the third period of that game, and the Rangers never really recovered.
Although in last place in the Atlantic Division with a 4-7-5 record, the Rangers have recovered after opening the season with four consecutive defeats.
But the Rangers recovered to win twice in Montreal.
The Rangers fell behind by four goals a little more than 11 minutes into the game and never recovered.
Worn out but unyielding, the Rangers recovered to win with Kovalev's emotional rescue.
It was only the finishing act of a wild one in which the Rangers squandered a three-goal lead but recovered to win their fifth consecutive game.
Celtic's amazing turnaround will mean nothing if Rangers recover to secure a fourth straight title.
Rangers had been 2-0 down at half-time but recovered to win the game after outclassing Jock Stein's side in the second 45 minutes.
The Bruins gained a two-games-to-one series lead from New York, but the Rangers recovered to win three straight games, defeating the first-place Bruins four games to two.
The Rangers recovered from that one nicely, though.