Jenson Button has tipped rival Mercedes GP to cause a surprise at this weekend's Canadian Grand Prix - as he expects it rather than Red Bull Racing to be McLaren's main threat.
With the long straights and lack of high-speed corners expected to not allow championship leaders Red Bull Racing to stretch its legs, many believe that it is McLaren who is favourite for another win in Montreal.
However, Button suspects that the advantage that Mercedes GP has with its straight-line speed, especially when it uses its DRS, could allow the Brackley-based team to deliver a stronger performance than many people expect.
"I think qualifying is going to be pretty tricky," said Button in Canada. "I think we will be a lot closer to the Red Bulls if not quicker than the Red Bulls, but you have to look at what Ferrari has got with their DRS and also Mercedes.
"There are a lot of straights here and we are very good at using our DRS. The system we have for using it is very good, we seem to be able to use it in more places than other people.
"But, with the long straights here - I think they can get about 20 km/h with DRS, the Mercedes, and I think most other teams are about 12 km/h. It is a massive difference around here, so in qualifying they are going to be very, very quick.
"They [Mercedes GP] are possibly our biggest competitors I would say, which I think is a little bit of a surprise to most people - or will be. They will be very competitive here."
Button is confident, however, that McLaren now has the race pace to match Red Bull Racing - even if qualifying remains an uncertainty.
"I think the last two races, we have been very close to beating Red Bull - and especially in one I think we should have, but they won the race.
"Our pace is as good as them in a race situation it seems, and here you have two DRS zones so it makes it very interesting that even if you cannot get pole position you can still challenge for a race win."
With Button on a high after his strong showing in the Monaco Grand Prix, the former world champion says he feels more comfortable in his car now than he has felt all season
"There is a lot that has changed at the rear of the car, in terms of the diffuser and the front wing. Lots of different areas have changed, and for me in Monaco the car felt the best it has all year.
"The rear stability was very good on entry which meant you could carry a lot of speed into corners.
"There are a lot of positives with the car, but also a lot of negatives - and when I was racing with Seb and Fernando [in Monaco] I could see there were weaknesses with our car. That is a good thing about having races like that; you can find the areas where you are weak."