Taylor Hall added a goal and an assist, and Brad Marchand tallied two assists as the Bruins rebounded from a 6-3 loss Wednesday in Philadelphia to salvage a split on its first road trip of the season. David Pastrnak and Thomas Nosek also scored for Boston.
The Sabres got a goal from Victor Oloffson in opening a back-to-back set with their first loss on a four-game homestand. Craig Anderson stopped 22 shots.
Coyle scored on a power play to give the Bruins a three-goal lead about five minutes into the second period. It was the first power-play goal the Sabres allowed this season after nine successful penalty kills.
Marchand threaded a pass from the right circle past three Sabres' sticks to set up Coyle on the left side of the net. Marchand also had a hand in the Bruins' first goal when he took the puck from Buffalo's Rasmus Dahlin along the end boards, received a backhand pass from Patrice Bergeron and fed Pastrnak for a one-timer from the right slot.
Coyle set up Nosek for a tap-in from the left edge of the crease to make it 2-0 toward the end of the first.
Hall assisted on Nosek goal and scored into the empty net in the closing minutes of the third period. Hall, who played 37 games for the Sabres last season before getting traded to Boston, drew boos in his first game back in Buffalo with fans in attendance.
Olofsson scored with 5:25 remaining in the third to end Ullmark's shutout bid.
Bruins: F Nick Foligno (upper body) is day-to-day after he left Wednesday's game in the second period. ? F Craig Smith was in the lineup after being held out of Thursday's practice with a minor injury.
Sabres: C Cody Eakin (undisclosed) sat out and will miss at least one more game due to an injury sustained when he crashed into a net during Wednesday's practice. ? D Mattias Samuelsson (lower body) skated with the team Friday for the first time this season.
Bruins: Host the San Jose Sharks on Sunday.
Sabres: Visit former coach Lindy Ruff and the New Jersey Devils in road opener on Saturday.