Kostopoulos, Jackman and Jarome Iginla scored in a 7:30 span in the second period and the Flames won their third straight game, 3-2 over the Avalanche on Friday night.
Miikka Kiprusoff made 19 saves for the Flames, playing their first game since Darryl Sutter resigned as general manager Tuesday. Assistant GM Jay Feaster is serving as acting general manager.
Kostopoulos and Jackman, playing on a line with center David Moss, also each had an assist.
"We feel like we've been playing hard and with a little bit of chemistry for a few games now," Kostopoulos said. "We seem to have a few bounces go in for us so it's nice that way. Moss and Jackman work hard every night so it's a lot of fun playing with them."
Jackman signed as a free agent in the offseason.
"We've just been generating some offense, getting the forecheck going," Jackman said. "It was nice tonight to be able to chip in a little bit."
Calgary coach Brent Sutter was pleased with the line's play.
"They played extremely well again," Sutter said. "They have just carried on the way they have been playing and that was just two huge goals for us tonight. I was very pleased with their play. It's an energy line that works and competes hard and does it to the details. They play the way we want them to play and they were rewarded for it."
"We were pretty resilient there in the third period, but it wasn't enough," Colorado coach Joe Sacco said. "It was a little bit too little, too late. At the end of the day it just wasn't good enough."
Kostopoulos opened the scoring at 5:53 of the second period when he drove to the net and swatted a rebound past Craig Anderson. Just 42 seconds later, Iginla took a drop pass from Alex Tanguay and wired a shot through traffic past Anderson. Jackman put Calgary up by three when he took a breakaway pass from Anton Babchuk and put a shot under Anderson at 13:23.
"I haven't had too many breakaways, so it's nice," Jackman said. "I was going to shoot it and then the guy hooked me and I just stayed there and slammed it home. That's about it."
Winnik got Colorado on the scoreboard with a short-handed goal at 7:45 of the third period. While falling to the ice, Winnik backhanded a shot through Kiprusoff's legs to end the goalie's shutout bid.
Fleischmann then backhanded a shot past Kiprusoff with 2:32 left.
"It wasn't good enough," Fleischmann said. "It's tough to play catch-up after 3-0. We tried. We had chances a little bit, but it was nothing close I would say."
- The Flames will play in Edmonton on Saturday, while tyhe Avalanche will return to Colorado for a game Sunday against Vancouver.
- The Flames have won six straight on New Year's Eve, dating back to Dec. 31, 2003, when they lost 2-1 to the Avalanche.
- Calgary forward Curtis Glencross has gone 14 games without a goal since scoring the 10,000th goal in franchise history Nov. 26 in a victory over Philadelphia.