SOCHI, Russia -- Force India's Sergio Perez is convinced Ferrari and Renault have drawn level with Mercedes' once-dominant engine, which he feels now only has a clear advantage over Honda.
After three years with the class-leading power unit Mercedes no longer enjoys the outright advantage it once did on the engine side, with its factory team seemingly set for a year-long title fight with Ferrari. In the midfield battle behind, Mercedes customers Force India and Williams have had competition from the Ferrari-powered Haas team, who believe the Italian manufacturer's engine might just be the best of the current crop, and a resurgent Renault.
Perez thinks Ferrari and Renault have made "massive" steps forward since the end of 2016.
When asked if the previous advantage of Mercedes' engine had gone at circuits like Bahrain and Sochi, he replied: "Yes. I definitely think that Ferrari is at the same level as Mercedes and Renault is more or less there. We only have the advantage to Honda."
Perez disagrees with the assessment that 2017's sweeping rule changes have made engine power less important than in previous seasons.
"It's the opposite I think. This year with these cars, the engines are much more important than in the past. The amount of time you spend full throttle is a lot less, and the amount you recover is also a lot less. Definitely Ferrari and Renault have done a massive step forward to catch Mercedes."
Force India struggled in Bahrain despite the fact the Sakhir circuit rewards cars with good power, something Perez blamed on its rough surface. With the Russian Grand Prix run on the Sochi Autodrom's smooth tarmac Perez is expecting a much stronger weekend.
"I think this track should be a bit better to us. I think Bahrain really exposed all of our issues in one go. It was also a very tricky weekend up to qualy with all the issues that I had personally with the car. I think Bahrain was always going to be a very hard race for us given the track layout, how it is. It was probably one of the hardest races for us. I think here we should be a bit more competitive. I at least have the hope that we can be more competitive and closer to where we should be."