Swail had become a perennial favourite through the Summer Series, but an Achilles injury suffered last November had hobbled his success this season.
The Leopoldo Palacios Jugo designed course had not been friendly to Swail on Saturday. Riding Martha Louise, Swail entered his final run sitting third-last in the field. But the Irishman stormed around the course, finishing with a time of 38.955 seconds.
Montreal's Eric Lamaze dazzled in his final performance of the day, posting a clean run that thrust him into the lead, more than two points ahead of his nearest competitor, but would have to settle for a second-place finish.
Halifax's Ian Millar had a less impressive day finishing tenth.