David Perron added two goals and an assist, and T.J. Oshie also had two assists as the Blues won for the fourth time in five games and improved to 15-0-3 in their last 18 at home.
Colaiacovo, stationed 20 feet from the net, got his elbow on Berglund's drive, re-directing it behind goalie Semyon Varlamov. It wasn't a picture-perfect tally but Colaiacovo, who has two goals this season, will take it.
"I didn't need my stick to put it in," Colaiacovo joked. "I felt it glance off my elbow. I didn't care who got it. I was just happy that it went in."
St. Louis, among the NHL's best home teams at 23-3-4, has recorded at least one point in a franchise-record 18 straight games.
Colaiacovo's 30th career tally helped the Blues improve to 15-0-3 in that stretch. They have outscored their opponents 53-30 during the home-ice run.
"We battled hard tonight and played an excellent game," Colaiacovo said. "At the end of the day we found a way to win. That's one thing about us. We've been finding a way to do it at home."
Colaiacovo broke a 37-game scoreless drought with his fourth shot on goal of the night.
"I didn't really have any other choice but just to throw it on the net," Berglund said. "Luckily, it got through and it went in. It's nice to get out of here with two points."
Colorado defenseman Erik Johnson said the puck bounced off several players on the way to the net.
"It hit two guys, including me," Johnson said. "That's just how it bounces sometimes."
Johnson and Shane O'Brien scored for the Avalanche, who snapped a two-game winning streak and dropped their sixth in eight games.
O'Brien put Colorado ahead 1-0 midway through the first period before Perron scored twice in a span of 4:05 later in the first to give St. Louis a 2-1 lead. Perron has five goals in his last three games, including a pair in a 3-1 win at Ottawa on Tuesday.
Johnson -- the top overall pick by the Blues in the 2006 draft -- tied it less than three minutes after Perron's second tally, breaking a 22-game scoreless skid.
The Blues bounced back and outshot Colorado 33-11 after the first period and held a 44-19 advantage overall.
"I'm proud with the way we stayed with it," St. Louis coach Ken Hitchcock said. "I thought we competed at a high level. Kudos to the players."
St. Louis goalie Brian Elliott made 17 saves and improved to 18-5-2. He made a big stop on Gabriel Landeskog with 3:45 left in the third period to keep the game tied at 2.
The Avalanche, who have five points in their last three games, kicked off a four-game trip.
"I like where we are at right now," Colorado coach Joe Sacco said. "We had an opportunity to block that last shot and we didn't. It takes a funny bounce and it goes in."
Johnson believes his team can build off the one-point effort.
"That's a good team that really wears you out in its own building," Johnson said. "Obviously, we'd like to get two but we'll take the one point."
Colorado RW Milan Hejduk played in his 967th game as a member of the Avalanche franchise, tying him with Adam Foote for second all-time. Joe Sakic leads with 1,378 appearances. ... The Avalanche lead the NHL with 18 one-goal wins. ... The Blues' 23 wins at home ties last season's total and is six short of the franchise record set in 1980-81. ... St. Louis is 24-0 when scoring three or more goals. ... The Blues are 27-1-3 in their last 30 home games with Perron in the lineup. ... St. Louis improved to 27-7-7 under coach Ken Hitchcock.
Copyright by STATS LLC and The Associated Press
ST. LOUIS, MO - FEBRUARY 11: Brian Elliott #1 of the St. Louis Blues warms up before an NHL game against the...