It was a pretty great mistake.

Probably the greatest in hockey history.

Haiden Kramer sniped Yukon Office Supply's game winner over Skookum Asphalt in the atom finals of the Whitehorse Minor Hockey Association year end tournament on Sunday.

The 11 year old was actually going for something different.

"I was actually trying to pass it to our captain, but then my stick sort of went up and got it top shelf,” Kramer said.

What did you think when you saw the puck go in?

"I can't believe I just did that.”

Kramer's goal was the 3-2 overtime winner.

Teammate Matthew Tremblay said the win was a "very good” way to ring in his 10th birthday on Sunday.

Office Supply held a birthday party for Tremblay in the dressing room following the game.

Complete with cake.

Kramer also opened his team's scoring.

Office Supply coach Gordon Campbell (not the former B.C. premier) said Kramer played great all tournament.

"A lot of these kids I've seen since they were five years old in tykes, so it's great to see him play so well, because you just know that he's got the skill,” Campbell said.

"It's an amazing way to win the season. We've been having really good luck all year. It was really interesting for them to go into overtime for them to win it, and it just shows that they really pushed that last little bit.”

The Office Supply went undefeated in the round robin with a 5-0 record.

In the WMHA season, the club lost just three games, one to each of the other teams, Campbell said.

"You could see when the other teams were playing us they took a big step up against us,” he said.

"We've had a strong team all year, and we've had lots of games where the kids haven't had to be pushed, so this was a great game for them to actually push and try harder and see what it takes to get to the next level. In that sense it was just wonderful.”