Barcelona F1 test: Nico Rosberg says Ferrari has made biggest step

The Italian team set the pace on three of the four days of testing at Jerez, and Kimi Raikkonen has been second-quickest on both days at Barcelona this week.

After Jerez, both Red Bull's Daniel Ricciardo and Williams' Felipe Massa said Ferrari's consistent speed throughout the test suggested the team could be a threat this year, and now Rosberg has added his voice to the argument.

"It's clear that the others have really stepped up their game," said Rosberg, who completed 66 laps on day two before handing the car over to Lewis Hamilton as a precaution as he recovers from a trapped nerve earlier in the week.

"The lap times are surprising to us and it seems Ferrari has made the biggest step at the moment."

When asked if Ferrari is a threat, Rosberg said: "For sure, yes. Our eyes are wide open at the moment."

Hamilton, who managed 89 laps in the afternoon session, added: "I've not looked at where we are, but I think others have taken a good step so I guess time will tell."

RAIKKONEN ENJOYING NEW CAR

Raikkonen, who hands the SF15-T over to new team-mate Sebastian Vettel for the final two days of the test, said it's clear "everything" has improved with Ferrari's car for this year.

"There is a good atmosphere," the Finn told reporters. "We've done a good job over the winter and I think we're going in the right direction in all areas.

"Obviously it's still early days but so far it's not too bad and it's enjoyable.

"We do our own stuff and we've been pretty happy with how things have gone."