Tkachuk and Demitra each had two goals and an assist to rally the Blues to a 5-3 victory over the Flames.
St. Louis took all four meetings with Calgary this season, sweeping the series for the first time since they went 3-0 in 1984-85.
“It was nice to see the scorers pick up the whole team,” said Tkachuk, who netted his team-leading 26th and 27th goals.
The Flames blitzed Brathwaite early, scoring three goals on 11 shots in the first 8:02. But the Blues clamped down defensively and yielded just nine shots the rest of the way.
“I was not too sure what was going to happen,” Brathwaite said when asked of the possibility of being yanked from his first start since January 21. “It was nice to stay in the net, to see that (coach Joel Quenneville) had confidence in me and to see that the guys had confidence around me.”
After Demitra beat Turek with a slapper from the top of the left faceoff circle at 4:13, Blake Sloan restored Calgary’s two-goal lead off a goalmouth scramble at 8:02.
Tkachuk took a pass from Demitra on a 2-on-1 and scored from the left slot to pull the Blues within 3-2 with 5:07 left in the first period.
Tkachuk tied it with a backhander from the right side of the slot off a rebound of a shot by defenseman Jeff Finley 3:25 into the second.
Tyson Nash put the Blues in front with 8 1/2 minutes left in the period. Turek stopped a shot by rookie defenseman Barret Jackman from the left faceoff circle, but Eric Boguniecki and Nash were positioned near the crease. Boguniecki deftly passed to Nash, who scored his fifth goal.
Demitra scored a power-play goal, deflecting a slap shot from the right point by defenseman Al MacInnis with 26 seconds remaining in the period.
“We worked hard for it, we bounced back and scored enough to take over the game,” said Demitra, who scored his 22nd and 23rd goals.
The Blues held Calgary to five shots in the third period.
“We did not keep up the pace when we were ahead 3-1 and could not get it back when we needed it later,” Flames coach Darryl Sutter said.
The loss extended Calgary’s winless streak to five games (0-3-1-1). It has just one win in the last 10 contests (1-6-2-1).
The Blues dropped the first two games of the homestand. Goaltender Brent Johnson squandered a three-goal lead in a 4-3 overtime loss to Philadelphia on Thursday and was pulled in the second period of Saturday’s 5-3 setback to Phoenix.
Quenneville started Brathwaite, who was acquired in the six-player deal that sent Turek to the Flames in June 2001. But the game did not begin well for Brathwaite.
Off a 3-on-2 rush, Iginla pounced on a rebound for his 24th goal.
“We did so well early, but they went to another level and we did not,” Iginla said.
Lydman’s power-play goal was a floater from the left point through traffic.
“We had talked about how they were going to come out fast, but we did not really think it was going to be that fast,” Brathwaite said.
Hearing jeers from the crowd, the Blues responded when Demitra scored on a slap shot off a pass by Tkachuk.
But the booing resumed when Sloan’s goal increased Calgary’s lead to 3-1.
“To start like we did was not good,” Quenneville said. “We were too loose, we gave up too many opportunities around our net and our coverage was sloppy. It wasn’t Fred’s fault that we fell behind early. But it was important that we found a way to battle back.”