After twice racing to four-goal leads, the Sharks downshifted into casual mode and sweated out a 6-5 victory.
The Blues had a 6-on-4 advantage for virtually the entire final minute of the third period.
The Sharks' penalty-killers Kyle McLaren, Josh Gorges, Marcel Goc and Patrick Rissmiller were under siege. Then McLaren managed to clear the puck with less than 10 seconds left to the secure the victory that pulled them one point behind the Ducks.
"We got fortunate enough to just get it out of the zone and then waste the time," McLaren said. "It was ugly, but we'll take it."
Linemates Joe Thornton and Jonathan Cheechoo each had a goal and three assists to help them jump to a 6-2 lead by 11:30 of the second period.
Bill Guerin completed his hat trick shortly after Cheechoo's goal to cut the lead to 6-3 heading into the third period.
"We sat back there in the third," McLaren said. "We have to learn from it. We just can't blow leads like that. We made it hard for ourselves tonight toward the end when we didn't have to. We have no one to blame but ourselves. We stopped skating, stopped shooting, sat back and watched them come in the zone too many times, and they capitalized.
Ryane Clowe and Matt Carle scoredin the first seven minutes of the game to make it 2-0.
Clowe connected just 39 seconds into match. After an icing call on the Blues, Thornton won the faceoff in the right circle. Cheechoo immediately gave the puck back to Thornton, who wheeled into the middle and located Clowe.
Unmarked on the doorstep, Clowe pumped in Thornton's feed as if he were executing a drill at hockey school.
Thornton and Patrick Marleau scored early in the second period to push the lead to 5-1.
"It was almost too easy to get the 6-2 lead," Sharks coach Ron Wilson said, alluding to several Blues' giveaways in the defensive zone.
"I kept saying to the team: 'You've got to put these guys away. They won't go away.' All the games I've watched on TV, when they have fallen behind by two or three, they manage to come back, and I thought they'd do the same."
The Blues trimmed the lead to 6-4 at 6:22 of the third when Keith Tkachuk jammed in a rebound. Radek Dvorak's shot handcuffed goalie Vesa Toskala to create the second chance.
Christian Backman's goal at 14:03 of the third made it 6-5.
"Our 'D' was really backing off," Wilson said of the passive play in the third. "When you're backing off and letting guys walk in to the top of the circle and fire bombs, the goalie's not going to be able to control rebounds. Then your job is to make sure you clear rebounds. We didn't do a very good job of it."
The Blues then went on a power play at 17:57 when Milan Michalek was whistled for tripping to set up the frenzied finish.
"You're doing your best to let the goalie see the shot," Gorges said. "But it shouldn't have come down to that point."
Despite the dicey ending, the Sharks could take some solace in their spreading of the offense. With Mike Grier also netting his 12th of the season, it was just the third time this season that at least six players accounted for the goals.
"But we've got to tighten up on defense when that pressure comes," Clowe said.