BOSTON -- The Bruins didn't have to be -- or want to be -- told how long it had been since they'd won two games in a row.
"January-something, I know that," Tyler Seguin said. "I knew it was too long."
Defenseman Johnny Boychuk broke a 1-1 tie at 12:56 of the third period and Krejci scored 2:58 later to make it 3-1.
The Bruins, who won at Toronto Tuesday night, last won two in a row since Jan. 10 and 12. It was the 11th time the Bruins had tried for two in a row since then.
"We've been obviously battling for consistency," Bruins coach Claude Julien said. "Even though this is our first back-to-back win in a long time, I was encouraged by our play in New York (a 4-3 loss to the Rangers Sunday) and it just kept coming along, in the next game, obviously winning and then tonight again we had a pretty decent effort.
"When you've got the amount of injuries that you have, you take every win for what they are and tonight was a good win for us."
The loss was the second in the last three games for the Sabres, who are battling for a playoff spot in the Eastern Conference.
The Sabres almost pulled out a point with backup Jhonas Enroth in goal for the first time since Feb. 12, as Ryan Miller got the night off after 10 straight starts. They lost for the second time in their last three games.
"I think it is a good example and shows you why they are where they are at right now, and where we're at," Buffalo captain Jason Pominville said. "They stuck with it, they were patient and they didn't really give up much."
Pominville scored in the first period and Boston's Gregory Campbell tied it in the second.
Tim Thomas made 19 saves for Boston.
With the game tied 1-1, Boychuk stepped into a loose puck after a sliding Jordon Leopold broke up Jordan Caron pass. Boychuk blasted his fourth goal of the season past Enroth, making his first start since Feb. 16.
Caron's assist on the goal gave him six points in his last three games.
Krejci has been Boston's best scorer since joining a line with wingers Seguin and Milan Lucic. All three players have at least one point in each of the five games and the line has 20 points (10 goals). It was Krejci's sixth goal in the last seven games, his 18th of the season.
Pominville walked down the right side on a 2-on-1 but Thomas had a clear view of his slap shot the hit the top of the net. It was the 25th goal of the season for Buffalo captain, the third time in his career he has scored 25, but the first time since 2007-08.
The Bruins ran up a 13-6 shots advantage in the first period but didn't score until the final minutes of the second.
Christian Ehrhoff's pass in the defensive zone hit the skate of teammate Cody Hodgson and headed out to the blue line. Shawn Thornton stepped right into the puck and his shot was deflected out of midair by Campbell and Enroth at 18:09.
The goal was reviewed but stood. For Campbell, it was his seventh goal of the season, first in 20 games.
It came just over five minutes after a shot by defenseman Dennis Seidenberg, beat Enroth and slammed off the goal post to Enroth's left. It came right out into the crease and the goalie covered it with his glove.
"I wasn't quite sure of the exact date (of the last two-game winning streak) but I know, we all knew, that it's been quite a while," Campbell said. "As we approach the playoffs you're not going to find yourself going very far if you're winning one, losing one so that's where the consistent factor comes in."
Boston's Brad Marchand, nailed by a clean check from Tyler Myers late in the game, appeared to injure his right shoulder or arm and didn't' play again, but Julien said he didn't play because of game circumstances and that Marchand was "ready to go." ... New Boston backup goalie Marty Turco, who cleared waivers to return to the NHL Wednesday, dressed as Thomas' backup. Turco was signed for the rest of the season because of the injury to Tuukka Rask. ... The Bruins wished a happy 94th birthday to former coach Milt Schmidt.