Colaiacovo's 26th NHL goal, scored midway through the third period, was the difference in the Blues' 2-1 victory over the Dallas Stars on Saturday night.
Colaiacovo's goal, scored 8:14 into the third during a scramble in the crease, was his first in eight career games against the Stars and his first game-winner this season. The defenseman backhanded the puck into the near side past goalie Kari Lehtonen to give the Blues their season-best fourth straight home victory.
Colaiacovo decided to pinch into the offensive play once the puck got into the low slot area.
"I just saw the opportunity with the puck up high," Colaiacovo said. "I tried to cheat down low for a rebound or even a backdoor pass. When the shot went through, I just happened to find myself still stuck there.
"Guys were crashing and banging and I just happened to be in the right place at the right time. I just tried to get it in there quick. Luckily for me, it went in."
T.J. Oshie added his 17th goal for the Blues, who moved within four points of Colorado and Calgary at the Western Conference's postseason cutoff. Chris Mason, who has won 11 of his last 16 starts, stopped 24 shots.
"It really is a roller-coaster," Mason said. "There's been points here in the last 10 games where we lose and we think, 'Oh, the season is done. We're this far out.' Then we put a good streak together and win three games in a row, and all of the sudden, we're right back in it. Then we lose a game, and all of the sudden, you're right back out again.
"We win tonight and things just get more interesting. Basically, what I'm trying to say is you can never quit, and this team has never quit."
The Stars, clinging to fleeting postseason chances, failed in their seventh attempt of the season to win three games in a row. They are the only team in the NHL without a three-game winning streak this season.
"It's hard to fathom," Stars center Brad Richards said.
The Stars got a power-play goal from Brenden Morrow. Lehtonen made 21 saves.
"We got good goaltending," Stars coach Marc Crawford said. "You've got to look at other areas. The last couple nights, we've worn out a few [of our] people. That was evident tonight."
Oshie gave the Blues a 1-0 lead 4:19 into the game when he hammered in Roman Polak's shot from the point that Lehtonen couldn't handle. Andy McDonald forced a turnover along the wall to get the puck back to the point.
Morrow tied it 1-1 with 1:49 left in the second. He won a battle in the slot with defenseman Mike Weaver and banged a shot past Mason.
Richards had six assists in four games against the Blues this season. ... Oshie has points in six straight games against the Stars. ... Blues C Keith Tkachuk and Stars C Mike Modano, who have hinted this season might be their last, have played in a combined 2,655 games, scored 1,094 goals, earned 1,326 assists and totaled 2,420 points. Tkachuk is in his 18th season. Modano is in his 19th. ... Blues LW Paul Kariya (lower body) and Colaiacovo (upper body) returned to the lineup after missing one game. D Barret Jackman (upper body) sat out. ... The Blues honored Kariya in a pregame ceremony for his recently scored 400th NHL goal.