The Calgary Flames would dearly love to replay the 51 seconds that cost them a precious two points.
Trailing by one, the Blues potted a pair of goals in the third period to upend the Flames 3-2 Friday night at Pengrowth Saddledome.
Centres Andy McDonald and Jay McClement notched goals in the final 20 minutes, giving the Blues a surprising road victory.
The Flames appeared to be cruising after the first 40 minutes, outshooting the Blues 20-11 and leading 2-1.
Calgary sat back in the third, allowing St. Louis to fire pucks at goaltender Mikka Kirprusoff with little resistance.
The team's lack of effort in the first 10 minutes proved disastrous.
First, McDonald took a Brad Boyes blind pass before sending the puck behind Kiprusoff at 9:24.
The Blues pulled ahead less than a minute later when McClement's wraparound fooled Kiprusoff.
"It wasn't a great shot by any means," said McClement of his first goal in 10 games. "I was just trying to get it on the net and maybe get a little action off of it — maybe a second chance — but thankfully it went in."
The loss was especially devastating to the Flames, who failed to put any distance between themselves and the Vancouver Canucks.
Calgary (41-24-6), which has lost five of its last seven games, remains in first place in the Northwest Division with 88 points, but is only three ahead of its division rival.
"Home ice is very important, but it's also important for us at this time of year to play properly, and to get better," Flames captain Jarome Iginla said. "We had a good game going until the third when they went bang-bang."
The Blues (33-30-9) move closer to making the Stanley Cup playoffs for the first time in five years, sitting only two points behind the Nashville Predators for the eighth and final playoff spot in the Western Conference.
"That's how we've been been getting our wins all year. We've had to fight for every point we've got and the guys didn't give up tonight," Mason said.
St. Louis goaltender Chris Mason sparked the victory with 33 saves, and centre T.J Oshie netted the Blues' first goal.
Mike Cammalleri and Dustin Boyd replied for the Flames, who also received a 25-save performance from Kiprusoff. Iginla chipped in with two assists.
"The most telling stat tonight — and it's a compliment of the effort of all the players on St. Louis' side — is they had 24 blocked shots to our six," said Flames coach Mike Keenan. "It's pretty telling about their effort and their desperation to win a game."
Calgary fell behind 1-0 at 4:04 of the first by surrendering a short-handed goal. After a Flames turnover at the St. Louis blue-line, Oshie was able to shake off defenceman Dion Phanuef to convert his own rebound past Kiprusoff.
Mason did his best to keep the Blues in front in the second period. The St. Louis netminder made a trio of terrific stops with Calgary on the power play, including a glove save off the stick of Iginla from the short side.
But the Flames got the tying goal on the same power play at 2:33 when Olli Jokinen spotted Cammalleri, who one-timed his career-high 35th goal of the season inside the post.
Calgary continued to pressure the Blues, resulting in a 2-1 lead 5:02 later. Boyd was able control a rebound in front of the St. Louis net and beat Mason.
Kiprusoff — not to be outdone by Mason — made his best save with 2:05 remaining in the second. With St. Louis on the power play, Kiprusoff stoned McDonald in the slot after snatching the puck out of the air.
Undeterred, McDonald and the Blues got their revenge.
"They just came out and won the third period and took it away from us. On our part we know that's unacceptable," Iginla said "It's our building and the third period has been ours all year. We let one slip away."
Calgary gets the weekend off but will face a tough week, with four games starting with Monday night's home game against Western leaders the Detroit Red Wings.
The Flames beat the defending Stanley Cup champions in a 6-5 comeback thriller on March 12.