Krejci and Smith scored in the third period on Tuesday as the Bruins rallied for a 2-1 win over the Calgary Flames.
"It was a really tough first two periods," said Smith, who is now tied with Krejci and Milan Lucic for the team lead with three game-winning goals each. "There's no excuse for that. We didn't have enough emotion, didn't have enough jump.
"We made it way too easy on them. We didn't have enough hits. We weren't turning pucks over. There were too many things going wrong to have a good solid start to the game."
After the Bruins (21-8-2) were outshot 22-9 through two periods, Smith said the players got a stern talking to from the Boston coaching staff during the intermission.
"The coaches came in and I think they did a good job trying to turn the momentum," Smith said. "We kept things a little simpler, got pucks behind their D and started playing back to Bruins hockey. The first two periods everything was going the wrong way, so it was good to see it turn around in just a couple minutes and be able to change the night around."
Shortly after Krejci scored a power-play goal at 13:49 of the third, Smith skated down the left wing, cut around Calgary defenceman T.J. Brodie and roofed a shot into the top corner over the outstretched glove of goalie Reto Berra.
"I tried to go hard to the net and I saw a stick come, so I tried to slip it under and just get a quick shot and it was lucky enough to find a hole," Smith said.
Boston coach Claude Julien definitely wasn't pleased with his team's play during the first two periods after which the Flames held a 1-0 lead.
"Those first two periods were really tough to watch," Julien said. "We just couldn't get anything going. Our true colours came out in the third. Somehow we've got to get our team to play three periods that way and stop pushing our luck here."
The Bruins have now won three straight games. After skating to a 3-2 win over the Pittsburgh Penguins at home on Saturday, the Bruins started their four-game road trip in Toronto on Sunday with a 5-2 victory over the Maple Leafs.
Jiri Hudler scored the lone goal for the Flames (11-15-4), who had won three of four heading into the contest.
"That's a bad way to lose," said Calgary captain Mark Giordano. "We had the game under control. We played a great game for two periods and it seemed like in the third, we were afraid to make plays and (were) giving them the puck pretty much all the time and it can't be like that.
"Teams like that, they're going to win. There's a reason they are who they are. We opened the door a bit and they took advantage."
Boston goalie Tuukka Rask finished with 26 saves to improve his record to 16-7-2. Berra meanwhile stopped 22 shots.
Tuesday's game marked the return of former Flames captain Jarome Iginla to the Scotiabank Saddledome for the first time since he was traded last March 27 to the Pittsburgh Penguins for a first-round draft pick and a pair of college forwards.
After playing in 13 regular season games and 15 post-season contests with the Penguins, Iginla signed on as a free agent with the Bruins in the off-season.
The Flames carried the majority of the play in the opening frame when they outshot the Bruins 11-5. Iginla had two of Boston's shots and also whistled a one-timer wide of the net during an early man advantage for the Bruins.
Hudler finally broke the scoreless deadlock at 5:17 of the second period when he snuck a snap shot from the top of the faceoff circle under Rask's glove and into the net.
Mike Cammalleri nearly put the Flames up 2-0 a short time later but his shot from the slot rang off the right post behind Rask.
After recording just four shots on net in the second period, the Bruins took the play to the Flames in the third as they outshot them 15-6.
"It seems like we just go into a shell and get away from what got us the lead in the first place," said Calgary forward Lee Stempniak. "We just chip pucks out and we're on our heels and we lack that aggressiveness that we had at the start."
Krejci tied up the game at 1-1 at 13:49 of the third when he tipped a point shot fired by Torey Krug past Berra.
Notes: Iginla's last game at Saddledome as a member of the Flames was on March 24 when he scored the game-winning goal in a 3-2 triumph over the St. Louis Blues. Iginla played one more game — a 2-0 road loss to the Chicago Blackhawks two nights later — before being traded to Pittsburgh. … Giordano, who succeeded Iginla as Flames captain this season, played his fourth straight game after missing 18 contests with a broken ankle. He recorded an assist on Hudler's goal to give him 12 points (three goals, nine assists) in 12 games.