Mercedes chief Toto Wolff supplies most worrying message yet over Lewis Hamilton F1 title bid

Mercedes has admitted for the first time that Ferrari are favourites for the world drivers' championship, over a quarter of the season into the 2017 campaign. Sebastian Vettel leads pre-season front-runner Lewis Hamilton by 25 points heading into the seventh race of the season at the Canadian Grand Prix in Montreal.

Vettel extended his lead in the title race after victory in Monaco as Hamilton was only able to finish seventh, following a poor run in qualifying. Finnish pair Valtteri Bottas and Kimi Raikkonen are third and fourth respectively but are not expected to feature in what is still a two-way duel for the title.

Ferrari are in the ascendancy after three seasons of unrivalled Mercedes dominance, which saw Hamilton win the title twice before Nico Rosberg prevailed in 2016. Mercedes co-owner Toto Wolff admits the team must come to terms with the fact it is no longer the favourite and must match the standard set by the Italians.

"It's painful, but we are not the favourites for this year's Championship," Wolff told the team's official website. "At the moment it's Ferrari. They have a very strong package and we need to rise to the challenge to prove once again that we are the team to beat.

"There are still 14 races left and everything is completely open. We're looking forward to Montréal and the chance to bounce back with a strong result – hopefully producing valuable answers to some tough questions in the process. We've come into this season with a strong car that has allowed us to win three of the first six races. But it has also caused us more complications than we have seen in previous years.

"This is the reality of the situation now. We have to fight with all that we are worth for every single win, pole position, podium finish and every point. You can no longer expect that, when you look at a timesheet, the two Mercedes will be right at the top."

The Silver Arrows have good reason to anticipate a strong showing in Canada this weekend though, with Hamilton having won five times in North America, including in each of the last two seasons, while Valtteri Bottas finished on the podium on both those occasions. Wolff says the pair will again be given license to race on a pivotal weekend in the championship.

"I'm expecting an interesting weekend in Canada," he added. "It could be a tricky race for us in terms of the layout of the track. But, equally, it's a circuit that suits both of our drivers. Lewis has won a number of times in the past and Valtteri has always gone strongly there for Williams.

"It will be about doing our homework right to give the drivers the car they need to succeed. We have two excellent drivers and we will hold true to our philosophy of letting them race each other to drive the team forward – even if sometimes it can be difficult because you can't always have the one who is ahead in the Championship winning."