The other factor playing against Hamilton is his engine with the news today that Mercedes will not be introducing a new, upgraded unit for this weekend over reliability fears.
Montreal wasn't kind to Mercedes in 2014 with Hamilton encountering brake issues that forced him to retire after 46 laps.
The 33-year-old Briton, who loves spending time in North America where he has additionally won the United States Grand Prix four times, arrived in Montreal on Tuesday night after visiting California, reportedly to check on his dogs Roscoe and Coco, and NY.
A quality issue meant Mercedes had to postpone the introduction of its second power unit of the season this weekend, resulting in Hamilton using the same engine he has used at all six races up to now.
The Brackley-based outfit had originally planned to bring the second of the three allocated engines each of Formula 1's 10 teams is provided with across the 21-race season.
Hamilton has a superb record in Montreal and victory on Sunday would see him match Michael Schumacher's haul of seven wins at the Circuit Gilles Villeneuve.
Hamilton said he was bewildered to find himself behind as Vettel emerged from the pits to hold on to the lead around the notoriously-restrictive Albert Park street circuit.
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The big loser could well be McLaren who have been the slowest in a straight line throughout this year and are unlikely to make up that deficit in other areas.
It will be a memorable weekend also for two-time champion Fernando Alonso, who is entered for his 300th Grand Prix and, potentially, his 298th start.
With Canada one of the most power sensitive circuits of the F1 season, Renault - Red Bull's engine suppliers - and Honda have both confirmed engine updates with Ferrari also likely to bring new internal combustion engine specifications.
Sauber and Williams will continue to linger towards the back but have shown they can get drivers on the fringes of the top 10 when running well.
Stroll earned his first F1 points at the Canadian Grand Prix previous year.
That is your look ahead to the possible stories to follow this weekend in Canada. Instead of that, we'll use the new one in Budapest.
"They'll be hard to beat", the Australian said.