Felipe Massa is in a realistic mood about Williams's chances ahead of this weekend's race in Monaco.
The British team was third overall in 2014 and 2015 but has fallen behind both Red Bull and Ferrari this year.
"I think we will be behind Mercedes, Ferrari and Red Bull," Massa told Brazil's UOL Esporte. "After that I think we're in a good position.
"I like Monaco. Or, I like it when we are competitive, but if you get caught behind, no one likes Monaco!"
The impression recently is that it may not be Mercedes or Ferrari but in fact Renault-powered Red Bull with the best chassis overall so far in 2016.
Massa said: "I don't think there is enough data to say that Red Bull is the best car. I think the Mercedes is also a very good car.
"[Mercedes] show it in every situation and at every track. The Red Bull is also good, better than the Ferrari maybe."
Massa placed 15th in last year's race.
