Fernando Alonso says his Ferrari team will have to raise their game as soon as possible if they are to close the gap to their rivals.
Ferrari is third in the constructors' championship ahead of this weekend's Bahrain Grand Prix, with Alonso having finished both races this season in fourth place.
Alonso insists that Ferrari has made strong progress since the final pre-season test at the circuit one month ago, but reckons the team still needs to work on the top speed of the F14T.
"Since the last test in Bahrain, we have made a big step forward in terms of the interaction between the electrical motor and the combustion engine," he said. "Everyone now has a better understanding of the rules, also for us drivers in terms of the driving style and how to manage this new Formula 1, so we come to this race with a much better basis than we had in the winter tests."
"The most difficult aspect of the Sakhir circuit is the braking, as there are long straights followed by heavy braking, then a tight corner and another straight. Braking performance and the feeling you get from the brakes gives you the confidence to attack and so get a better lap time. Apart from that, another priority will be to work on our top speed."
The Spaniard is expecting this weekend's twilight race to present a challenge to the teams in terms of both fuel and tyres.
"We have seen different types of racing over the first two Grands Prix, with the first one highlighting fuel saving a bit and the other shifting the focus to tyre management because of degradation, due to the high temperature," he said.
"I think Bahrain will feature a combination of both these factors. We will have to save fuel more than in Malaysia and the tyres will be affected by the temperature in the Bahraini desert. We can expect a tough race, as some of the competition is very strong and we will have to raise our game to close down the gap as quickly as possible."