Mercedes motorsport boss Toto Wolff has warned his team that "there is more to come from our competitors" ahead of the Austrian Grand Prix.
The Brackley squad have a healthy 105-point lead over Ferrari in the Constructors' Championship on the back of their fourth 1-2 finish of the season in Montreal a fortnight ago.
Lewis Hamilton and Nico Rosberg also occupy the top two spots in the Drivers' standings, but everyone will be keeping a close eye on Ferrari after the team's engine upgrade not too long ago.
"Coming away with another top result in Canada, it would be easy to sit back and think we've got everything under control," Wolff said.
"But in reality, this is never the case. Not only did that race require a careful balancing act from the pit wall and from the drivers, but we also saw that there is more to come from our competitors – even if maybe it wasn't clear from the result. There must be more to come from ourselves if we are to continue this good form."
Mercedes were given a run for their money at last year's Austrian GP with Felipe Massa taking pole position ahead of his Williams team-mate Valtteri Bottas and Nico Rosberg starting P3 with Lewis Hamilton down in ninth.
However, Rosberg went on to win the race with Hamilton finishing second.
Wolff added: "Austria will provide a tough test. We had a challenging weekend there last year and fully expect another close competition this time around. The battle is far from over."