The Oscar-winner was joined on the red carpet by his long-time friend Ben Affleck, who had nothing but praise for the runners.
"It was just amazing to me. I'm literally a guy who can't run five miles I don't think. The scale between me and these men is so dramatic," Affleck told CTV News.
On Sunday, Damon will host the annual One X One benefit gala held at the Four Season's Centre for the Performing Arts.
The gala will honour the Sahara running team along with Assembly of First Nations National Chief Phil Fontaine, Golden Globe winner Richard Gere, Duchess of York Sarah Ferguson and supermodel and philanthropist Petra Nemcova.
ONE X ONE is a nonprofit foundation committed to preserving and improving the lives of children in Canada and around the world.
Last year's gala, also hosted by Damon in Toronto, was hailed as a success after it filtered more than $1.3 million to Canadian charities.