Mercedes team boss Toto Wolff is starting to feel the pressure from rival teams this year, saying his outfit has "no breathing space" in the championship battle.
The standings tell a slightly different story, with Mercedes taking five victories in the opening six races and holding a comfortable 67-point lead over nearest rivals Ferrari. However, a series of reliability issues have been linked to the team's pursuit of extra performance and Wolff insists the title race is closer than it looks.
"I've said this many times before -- but we have no breathing space in this championship," he said. "Maintaining any advantage is a constant battle -- and the pressure is only getting bigger.
"This unpredictable season has been great for the sport and shows that Formula One is alive and well. But, for us as a team, there is clearly work to do. There remains room for improvement in our reliability -- but the push for more performance has become increasingly important too.
"We saw the 50th Formula One win for the Silver Arrows in Monte Carlo, which is a great achievement. But if we are to build the long-term success that puts Mercedes-Benz up there with the iconic names of this sport, we will need to push harder than ever."
Technical boss Paddy Lowe said Nico Rosberg's lack of performance in Monaco had been the main focus ahead of this weekend's race in Canada.
"We came away from Monaco pleased to have won there for a fourth consecutive year -- but not entirely satisfied after a tough afternoon for Nico. We've put a lot of effort into understanding why that was and have some good insights to take forwards into future races.
"Montréal is an unusual circuit, with plenty of low-speed corners linked by a good number of straights. It's a track that is therefore very demanding of both the Power Unit and the brakes.
"It's also a tricky circuit in terms of tyres. We'll see the second appearance of the ultra-soft compound this weekend - which should mean a notable drop in qualifying times relative to 2015. However, the track is far more aggressive on tyres than Monaco, so understanding how best to use the ultra-soft for the race will be one of the main challenges."