With the game tied in the 89th minute, Nick DeLeon sent a long pass downfield to an open Altidore, who buried the chance. It was the striker's first goal in eight games in 2020, as Altidore has been hampered by injuries, fitness concerns and a lot of missed chances.
One of those tough misses came earlier in Wednesday's game, as Altidore had a clear shot in the box in the 81st minute that was stopped by goalkeeper Clement Diop.
Toronto FC (6-2-3, 21 points) snapped a two-game losing streak, which included a 1-0 loss to the Impact on Sept. 1.
Toronto improves to 3-1-0 in four games against Montreal this season. All four games have been played within the last two months.
Pablo Piatti gave Toronto FC the early lead in the 32nd minute. Midfielder Richie Laryea made a spectacular run down the far side to set up Piatti's third goal of the season.
Laryea returned to Toronto's lineup after missing three games due to an ankle injury. Toronto FC made three changes (inserting Laryea, Altidore, and Chris Mavinga) to the starting 11 that suffered a 3-2 loss to the Vancouver Whitecaps last Saturday.
Victor Wanyama equalized for the Impact (4-4-1, 13 points) in the 57th minute, albeit in delayed fashion.
A Montreal free kick led to Wanyama heading the ball into Toronto FC's net, though the goal was initially discounted due to an offside call. The referee changed the decision after a video review, however, and Wanyama had his first goal since joining the Impact in March.
The Impact missed an early opportunity when Zachary Brault-Guillard sent a tremendous pass across the box to Saphir Taider in the 10th minute. Taider was open for a header but his shot went off target.
Toronto FC outshot the Impact by a 13-6 overall margin, and 10-3 in shots on goal.