But Nick Bonino, Radim Vrbata and Chris Higgins scored in the shootout for the Canucks, to give them a 6-5 win over the Blues and gain a crucial two points in the Western Conference's playoff race.
"It's not what we wanted to happen, blow a three-goal lead in the third, but some resiliency there, we battled back and got the two points," said Bonino, who admitted Vancouver needs to be better at holding on to a lead.
Eddie Lack was called in to action early and often throughout the game, making 34 saves for Vancouver (36-23-3), while Shawn Matthias, Yannick Weber, Jannik Hansen, Henrik Sedin and Bonino all had goals in regulation time.
"I was thinking to myself if the boys score five for me and we can't win, there is something wrong," said Lack. "It was a weird game and I kept battling and it's a very big win for us."
Ryan Reaves, Alex Pietrangelo, Dmitrij Jaskin, Petteri Lindbohm and David Backes replied for the Blues (40-18-5), who scored three goals in the third period to force extra time. Vladimir Tarasenko had the lone goal for the Blues in the shootout.
Jake Allen made 21 saves over 58:43 of work, while Brian Elliot stopped five of six shots in a brief third period appearance.
Bonino made it 5-2 for the Canucks at 6:07 of the third, assisted by Weber and Vrbata, with Elliot getting pulled as a result.
Allen said the brief respite hurt his game and affected his shootout performance.
"I've never experienced that before," said Allen. "Really weird, odd, felt a little uncomfortable and obviously I am usually pretty good in shootouts, I was just sort of mentally out of it a bit."
Paul Stastny helped the Blues offence come alive when he threaded a pass to Jaskin, who scored on the power play to make it 5-3 at the 8:18 mark of the third.
St. Louis struck again when Jaden Schwartz's backhand pass found Lindbohm near the faceoff circle and his shot made its way past Lack.
T.J. Oshie passed from behind Lack's net with Backes tapping it by the goalie at 15:31 to tie it 5-5.
Reaves opened the scoring for St. Louis 3:02 in to the first period, putting his shot past Lack from near the faceoff circle.
Lucas Sbisa compounded the Canucks' poor start as he slipped skating out of his own end, allowing Backes to steal in and slip it to Oshie. Oshie laid it off to an onrushing Pietrangelo who beat Lack at 5:59 of the first to double the Blues' lead.
Matthias responded for the Canucks two minutes later and Yannick Weber made it 2-2 at 9:40 of the first period.
"It's a two-goal lead 10 minutes in you want to stay on the gas and not let them have any air. It wasn't the case," said Backes of his team's mid-game collapse.
Vancouver came out stronger in the second period.
After missing two chances, Hansen buried his third at 10:15 of the second. His shot looked to be initially saved by Allen, only for the puck to hit the back of the goalie's thigh and trickle in.
There was initial controversy as an official's whistle seemed to have been blown, only for the play to be reviewed and a goal awarded.
"That's a goal that should never go in in this league and not much more I can say," said Allen. "I thought the whistle was blown but I didn't know where the puck was."
Notes: The Canucks have their second game in this homestand playing the San Joe Sharks on Tuesday. … The Blues continue playing on the road facing off against the Philadelphia Flyers on Thursday night.