Reilly Smith had a power-play and an empty-netter for Boston, which won its seventh straight at home. The Bruins haven't lost there in regulation since late October, going 12-0-2 in their last 14 games.
Zemgus Girgensons scored for the Sabres, who beat the Bruins 4-2 in Buffalo on Thursday night. The Sabres, who haven't won three straight this season, had a two-game winning streak broken.
Tuukka Rask, who was rested Thursday, made 34 saves, including a pair of key stops early in the third period.
Buffalo backup Jhonas Enroth stopped 35 shots and dropped to 1-7-3.
Krejci's goal broke a 1-1 tie early in the second period. Trailing and coming down the centre of the ice, Krejci took a drop pass from Jarome Iginla before waiting and firing a wrist shot past Enroth's glove.
Krejci fed Lucic in the slot from the left circle, and Lucic beat Enroth with a wrister inside the left post.
Smith scored with 21.4 seconds left.
The Bruins were short-handed two players for a lengthy stretch in the second period after Patrice Bergeron was called for cross-checking, and Gregory Campbell got a four-minute penalty for high-sticking Jamie McBain 11 seconds later. Boston held Buffalo to two shots during the initial 1:49 stretch, and one when they were down one man.
Boston was short two players again with just over 6 minutes left in the game, but Buffalo's Steve Ott got a slashing penalty seconds into the advantage.
Boston took a 1-0 on Smith's power play goal 9:39 into the game. Carl Soderberg sent a pass across the top of the crease to Smith, who one-timed a shot into an open side of the net.
The Sabres tied it late in the period when Girgensons banged in the rebound of Matt Moulson's shot. Moulson's wraparound attempt popped into Rask's stick side.
NOTES: Bergeron had his first career regular-season fight late in the second period, taking on Sabres defenceman Tyler Myers. ... The Sabres had killed 14 straight penalties before Smith's goal. ... Marchand was helped off the ice midway into the first period and was assisted down the runway to the dressing room area before returning to action a few minutes later. ... Bruins forward Shawn Thornton, who is appealing his 15-game suspension for taking down, punching and injuring Pittsburgh's Brooks Orpik, watched from the press box.