Gardiner was starring on defense for the University of Wisconsin at the time against the University of Michigan.
The game featured several current NHL stars, including Gardiner, Detroit Red Wings defenseman Brendan Smith and New York Rangers forward Derek Stepan and defenseman Ryan McDonagh. All four players were Wisconsin teammates. Rangers forward Carl Hagelin was playing for Michigan.
"We won 3-2 against Michigan and Brendan Smith scored the winner [at 18:38 of the third]," Gardiner told NHL.com. "We had a good team and it was fun to be out there in front of 55,000 people."
Smith scored twice and Stepan had two assists in the game. The outdoor contest in Madison, Wis., marked the second largest crowd ever to watch a collegiate hockey game.
Now, Gardiner is anticipating his first outdoor game on the NHL level when 2014 Bridgestone NHL Winter Classic is staged between the Maple Leafs and Detroit Red Wings at Michigan Stadium in Ann Arbor on New Year's Day.
"This game will double that crowd we had in Wisconsin so it's going to be even cooler," Gardiner said. "I remember how excited we were to do that and our student section was huge. We had so much support from them and I'm sure it will be the same here at the Winter Classic."
Gardiner said he has been keeping up on HBO's "24/7" series involving both teams. He said he enjoys the attention the team has been getting.
"It's not too much different from the amount of media coverage we get on a regular basis in Toronto anyway," Gardiner said. "I think guys are enjoying the [HBO crew]. We're having fun with it and the show has been great. I've watched every episode so far so it's been cool to watch. It's been a positive thing."
Gardiner even acknowledged that there's a chance he may receive some television time in a future episode.
"Me and [Morgan Rielly] recently did something in front of the camera, so hopefully I'll be able to see how that goes," he said.