Thanks to a nice pass from Alex Tanguay, Iginla found himself on a partial breakaway. St. Louis defenceman Wade Redden made a nice play to knock the puck away from Iginla, who stuck with the play to score a wrap-around goal.
Roman Cervenka scored twice and Miikka Kiprusoff stopped 36-of-38 shots as the Flames (12-14-4) snapped a three-game losing skid while extending their winning streak on home ice at the Scotiabank Saddledome to seven straight games.
T.J. Oshie had a goal and an assist for the Blues (17-12-2), who had won four of their past five games including a 3-0 win in Edmonton over the Oilers one night earlier. Vladimir Sobotka also scored for St. Louis.
St. Louis goalie Jaroslav Halak, who stopped all 19 shots he faced in the win over Edmonton, made 14 saves against Calgary.
It took until almost the 10-minute mark before Jiri Hudler finally recorded Calgary's first shot of the game.
Cervenka then scored on the second shot of the contest for the Flames when he took a pass from Dennis Wideman and wired a shot to the top corner past Halak during a Calgary power play.
Cervenka put the Flames up 2-0 at 9:40 of the second when he made a nice forehand-to-backhand move before lifting the puck up and over Halak. Mikael Backlund also made a nice play by keeping the puck in at the blue-line and tapping it ahead to Hudler, who set up Cervenka.
The Blues were then finally rewarded for their persistence when Oshie scored an unassisted goal at 16:40 of the second. Oshie stepped out of the penalty box and stripped Wideman of the puck before snapping a shot past Kiprusoff.
Although they outshot the Flames 19-4 in the second, the Blues still trailed 2-1 heading into the third.
St. Louis nearly tied up the game early in the third period but Redden's heavy shot from the point hit the left post behind Kiprusoff and deflected wide.
Sobotka pulled the Blues even with a goal at 4:48 of the third when he tapped a goal-mouth scramble through Kiprusoff's legs.
Notes: Oshie scored in his second straight game after sitting out the previous three with an injury to his ribs. … In Calgary's past eight games, Cervenka was a healthy scratch three times and failed to record a point in the other five contests. … After starting the season with two goals and 17 points in 24 games, St. Louis defenceman Kevin Shattenkirk has gone seven games without recording a point. … Although they've been hot at home, the Flames have been miserable away from the Saddledome as they've lost nine straight decisions on the road, going 0-8-1 in that span.