Tsyplakov cut the lead to 2-1 at 12:50 of the first. He took a pass from Nelson while cutting to the net and beat Korpisalo five-hole with a backhand.
Nelson tied it 2-2 at 8:52 of the second period. Bruins defenseman Mason Lohrei had the puck hop over his stick in the neutral zone, allowing Nelson to pick it up, skate in on the rush, and roof a shot over Korpisalo's glove from the right circle.
Morgan Geekie put the Bruins back in front 3-2 at 11:59, scoring into an open net from the bottom of the left circle off a pass from Zacha. The play started after Romanov hit Kyle Palmieri in the helmet on a clearing attempt.
Nelson tied it 3-3 with eight seconds remaining in the period, beating Korpisalo short side under his blocker from the left circle.
“Both teams make mistakes, you got to limit them,” Islanders defenseman Ryan Pulock said. “At times [we’re making] too many. When one happens, we need to find a way to come together and fix the problem. And right now, we are just not finding that.”
NOTES: Marchand scored his seventh career opening-minute goal to give the Bruins a 1-0 lead 57 seconds into the contest. The only players in franchise history with as many are Patrice Bergeron (10), Ray Bourque (9), Terry O'Reilly (7) and Phil Esposito (7)...Marchand later secured his 64th career multi-goal game to surpass Rick Middleton (63) for fifth most in franchise history and tie David Pastrnak for the fourth most...Pastrnak notched his 80th career multi-assist game in the win over the Isles to surpass Ales Hemsky (79) and Robert Lang (79) for the eighth most by a Czechia-born player...the three-assist night was also his 64th career three-point game, surpassing Ken Hodge (63) for seventh place in franchise history behind Esposito (140), Bourque (118), Bobby Orr (109), Johnny Bucyk (106), Middleton (87) and Marchand (65)...Zacha netted his 10th game-winning goal since joining the Bruins in 2022-23.The only Boston skaters with more in that span are Pastrnak (20) and Marchand (13).