Keith Thaxter gritted his teeth as he crossed the finish line.

The Whitehorse runner had finished the ultra category of the Klondike Trail of '98 International Road Relay in considerable pain.

Suspicious he was running on a hairline fracture in his foot, Thaxter clocked a winning time of six hours, 16 minutes and 38 seconds over the 72-kilometre ultra course between Carcross and Whitehorse.

"My legs are a little numb,” he said moments after crossing the finish line.

"I feel better this year than last year, only because I think last year I went too hard and probably blew up about the last 20 km, whereas I ran the first part here today a bit slower, so it was better. But I'm happy, considering I had a foot injury and I couldn't walk six weeks ago.”

Thaxter said he injured his foot while trail running earlier this summer.

He struggled mentally about whether or not he should compete in this year's relay.

"I think it's more like a hairline fracture, so I just waited and spent a lot of time today doing different strides, shorter and longer, to keep even pressure on the foot,” he said.

"I just kind of took it easy. Unlike the past, where I tried to run the first few legs harder and then slow down, I just tried to run an even keel on this one.”

Last year, Thaxter finished second in the ultra category with a time of 5:52:00.

In the 2010 road relay, Denise McHale smashed Thaxter's old ultra record of 5:45:13, which he set in 2009, with her own time of 5:28:00.

McHale opted out of this year's relay after finishing fifth with her husband Greg in the Gore-Tex TransRockies Run in Colorado in August.

Thaxter, who regularly runs with McHale, said having a companion of her caliber to train with is a good motivator.

"It's good to have competition,” he said. "But otherwise I was pretty much by myself, for the most part.”

Too bad.

Thaxter likely would have brought a smile to the faces of other runners with his Mickey Mouse costume.

"I thought it'd be good to dress up,” Thaxter said. "I was talking to the organizers, and I thought, it was a fun event so why not dress up in a fun costume. I thought Mickey Mouse was good.

"Just to add a little more excitement to the event, right?”