"We're playing with a lot of confidence right now," Richards said. "When you play with confidence, you think you can win every game. Tonight we played a little bit slower to start but got our legs and got a couple of bounces."
Carter is second in the NHL with 22 goals, two behind Buffalo's Thomas Vanek.
"It's a funny thing sometimes," Lupul explained. "At the start of the year we couldn't get a break to win a game. Now we're getting goals that bounce off the glass and come back and hit the goalie. It's a nice feeling. You know it's not going to last forever."
Paul Stastny and David Jones scored for the Avalanche, who had won three of four -- including a 2-1 victory Monday at Detroit.
"I wish a couple of tips could have gone in, but they made some big saves," Stastny said. "But I thought we played well."
The Avalanche had beaten the Flyers five straight times. Philadelphia's previous win over Colorado was 2-1 in overtime in 2002. The Flyers hadn't won a meeting in Philadelphia since 1999, also in overtime, 5-4.
Peter Budaj, who has started in 26 of Colorado's 31 games, made 19 saves.
Stastny, who leads the Avalanche in scoring with 27 points, put Colorado ahead with an unassisted power-play goal at 9:23 of the first period. His eighth goal came six seconds after Darroll Powe was called for hooking.
The Flyers responded with a power-play goal by Knuble at 11:37 and a short-handed score by Carter at 18:12 to take a 2-1 lead.
Knuble scored his 100th goal as a Flyer, poking in a shot from the crease after taking a cross-ice pass from Richards on a power play.
Carter scored on a one-timer after Gagne picked up a loose puck deep in the Flyers' zone, skated in and slid a pass to Carter in front of the circle.
The Flyers extended their lead to 4-1 with a pair of bizarre goals within a span of 1:18 midway through the second period.
Lupul's shot from in close bounced off the crossbar straight down into the net at 11:24.
Richards was given credit for a goal at 12:42 when Colorado's Scott Hannan inadvertently knocked the puck past Budaj during a scramble. Richard's shot bounced off the back glass and then off the top of the net and the goalie before falling in front of Hannan.
Philadelphia coach John Stevens said that such lucky bounces are the result of hard work.
"You can go back a little bit in the beginning of the year when I thought in the first six games [all losses] we had some unfortunate bounces," Stevens explained. "It just seemed that the harder you worked, the bounces turn in your direction. They have a way of evening themselves out."
Colorado made it 4-2 when Jones deflected T.J. Hensick's shot between Niittymaki's pads with 1:21 left in the period.
Gagne deflected Kimmo Timonen's slap shot from the blue line on a power play for his 16th goal at 2:14 of the third period. Timonen, who had two assists, has six assists in his last two games.
"The Flyers are real good on the power play and penalty kill," Jones said. "I think that's where the game was won today."
Richards extended his points streak to eight games (seven goals, eight assists). ... Colorado killed off 12 straight penalties before Knuble's power-play goal. ... The Avalanche are in the midst of a four-game road trip, their second-longest of the season, with games remaining at Tampa Bay and Florida. ... The Flyers lead the NHL with 12 short-handed goals, one less than their 2007-08 total. ... The Flyers recalled goalie Scott Munroe from the Philadelphia Phantoms, their American Hockey League affiliate.
Copyright by STATS LLC and The Associated Press
Arena: Wells Fargo Center Location: Philadelphia, Pennsylvania
Referees: Tom Kowal, Chris Lee Linesmen: Derek Amell, Steve Barton
Attendance: 19,219 (98.6% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Paul Stastny (8)
(Power Play) Unassisted
Mike Knuble (13)
(Power Play) Assists: Mike Richards, Braydon Coburn
Jeff Carter (22)
(Shorthanded) Assists: Simon Gagne, Ossi Vaananen
Joffrey Lupul (10)
Assists: Kimmo Timonen, Scott Hartnell
Mike Richards (13)
Assists: Simon Gagne, Mike Knuble
David Jones (5)
Assists: T.J. Hensick, Adam Foote
Simon Gagne (16)
(Power Play) Assists: Kimmo Timonen, Mike Richards