Marko: It’s still a two-horse race

Red Bull advisor Helmut Marko has warned that Mercedes will remain in a class of their own despite Ferrari and Honda's recent engine upgrades.

Merc have dominated Formula 1 since the new V6 engine regulations came into effect at the start of the 2014 season, winning 16 of the 19 races last year and five of the first six events this campaign.

Ferrari, though, have taken a few steps forward in 2015 as they are lot closer to their Brackley rivals than in 2014 and Sebastian Vettel proved in Malaysia that they can upset the applecart if conditions suit them.

In attempt to move even closer to Merc, Ferrari have used three of their in-season engine development tokens ahead of the Canadian GP while Honda, who are powering McLaren, have used two as they look to join the battle for podiums.

Mercedes, by contrast, have opted against utilising some of their tokens and will instead just use new power units in both Lewis Hamilton and Nico Rosberg's cars in Montreal.

Merc executive director (technical) Paddy Lowe admitted they are wary of their rivals, saying: "We suspect our competitors may also bring new Power Units, which this year may be upgraded in-season using development tokens, so it will be interesting to see whether and how the 'balance of power' is shifted this weekend."

However, Marko has played down suggestions that the rest of the pack will catch up any time soon.

"The Mercedes engine is still so superior that they don't need to use their tokens at this stage," he told Germany's Sport Bild.

"They are always playing with us. Hamilton and Rosberg will continue to battle for the victories between themselves."