Mercedes' F1 testing performance a big warning

The world champion team managed to cover 675 laps across the opening four days at Barcelona, over 200 clear of nearest rival Toro Rosso.

Asked by Autosport if that felt like an ominous warning to the opposition, Massa replied: "Them doing so many laps is already a big warning for the season, along with what they did in the last two years and how they finished the season, and the car they have and with the same rules.

"It is a warning whatever the situation. What they're doing on the track definitely shows they're going to be very, very strong again."

Massa's own running was limited on Thursday by an ERS problem that meant he could only cover 54 laps.

"It was not really a great day," he admitted.

"We didn't do as many laps as we did yesterday and today we had some issues that took time to change in the car.

"I think the only positive thing is that we did our aerodynamic tests in the morning to try to analyse all the numbers around the car.

"We've lost massive time today and it was not a very useful day.

"I hope it won't disturb our understanding of the car."