Brad Richardson opened the scoring 9:02 into the first period. He took the puck at the left faceoff circle and wired it low past a screened Dwayne Roloson. After the goal, Colorado had an 8-2 edge in shots over Edmonton.
Patrick Thoresen had a great chance to tie the game with about five minutes left in the first. Horcoff made a centering pass to Thoresen in front of the net but his wrister went over the blocker of Budaj.
With three minutes to go in the first, Roloson stopped Brett McLean and then came across to make a nice pad save off Paul Stastny as he attempted to backhand it over the Oilers netminder.
Colorado had a 14-5 edge in shots after one period of play.
52 seconds into the second period, Joe Sakic took a pass from Milan Hejduk in the slot and one-timed it by Roloson to increase the Colorado lead to 2-0.
At 7:21 of the middle frame, Hemsky scored to make it a 2-1 game. Hemsky took a pass from Thoresen before taking the puck behind the Avalanche net and wrapping it in.
Raffi Torres and Joffrey Lupul skated in on a two-on-one several minutes later. Torres elected to shoot and his shot went wide.
Outstanding forechecking deep in the Colorado end by Horcoff and Hemsky resulted in Edmonton's second power play of the night.
On the ensuing power play, Sykora teed up a blast from the high slot that Budaj barely saw as it whizzed past him into the top corner.
Late in the second, Dwayne Roloson took over while Colorado was on teh power play. He made several unbelievable saves, including a blocker stop on Paul Stastny that looked like a sure goal. He also denied Hejduk in-close.
After two, shots were 27-16 for Colorado.
A penalty to Brad Winchester early in the third gave Colorado another power play and they capitalized again.
Marek Svatos jammed the puck past Roloson during a goalmouth scramble to move the visitors back into the lead at 3-2.
Edmonton almost tied the game midway through the third after Hemsky hammered Avs defenceman Jeff Finger into the boards before centering the puck to Thoresen. Budaj made a good stop on Thoresen in the slot and the Norewegian winger couldn't find the rebound.
Stastny got a partial breakaway with 5:32 left bt the effort of Tom Gilbert to get back into the play and a nice blocker save by Roloson kept it a one-goal game.
With 1:47 to go, Joffrey Lupul took advantage of a miscue from Avs defenceman Kurt Sauer and pounced on a loose puck at the Colorado blueline. He then wristed it low, beating Budaj through the five hole.
The goal sent the game into overtime, knotted at 3-3 despite Colorado doubling up Edmonton 42-21 in shots.
Matt Greene almost ended the game with 2:21 left in overtime. Hemsky made a nice move on the side boards before setting up Greene in the high slot. The big defenceman took a few strides before blasting a shot. Budaj had to be sharp as Horcoff was right in front to pick up the rebound.
In the shootout, Roloson made an amazing glove save on Svatos during Colorado's first attempt bettered only by his glove stop on Sakic two shooters later.
Hemsky, Sykora, Pisani, Lupul, Reasoner
Svatos, Hejduk, Sakic, McLean, Wolski