Despite being happy after claiming his fourth pole of 2018 at the Canadian GP on Saturday, Sebastian Vettel admitted his surprise at Red Bull's approach in qualifying

The Ferrari driver was back at his best in Montreal, doing enough to beat the Mercedes of Valtteri Bottas and start at the front of the grid in Sunday's race, setting a best time of 1m10.764s.

After leading all three practice sessions in the build-up, Max Verstappen had to produce an excellent lap just to claim third for the German's former team, beating Lewis Hamilton in the process.

But it was a decision Red Bull made earlier in the session, in Q2, to complete their best lap on the Hypersoft tyre and not the more durable Ultrasoft, which Ferrari and Mercedes had on their cars, which confused Vettel as it means both Verstappen and Daniel Ricciardo will use that compound in the first stint.

"I don't think the Hypersoft is a good race tyre," the four-time world champion stated to Autosport.

"We were briefly talking about what we wanted to do, trying to figure everything out. For me, it was pretty straightforward, and in terms of strategy we did what we wanted to do.

"I'm a bit surprised that both of the Red Bulls chose that, but I guess they have their reasons."

The likely reason is, at the first race the pink-striped Pirelli was used two weeks ago in Monaco, Red Bull was the only team to really extract a good race pace from it without suffering from too much graining or degradation.

So far this weekend, it has looked more durable with drivers able to push for several flying laps and less degradation over a long run all of which means Verstappen is comfortable with the direction his team has taken.

"We think it's a good tyre for us, and in the long run [in practice] I felt good on it," he explained.

"No big surprises. We thought that Ferrari and Mercedes were going to qualify on the Ultras."

Indeed, the German manufacturer has stayed as far away from it as possible, only using it in the two sessions on Saturday and hope to complete a one-stop strategy using the Ultra and Supersoft compounds in the 70-lap race.