Williams' George Russell says Alfa Romeo produced in his view the most surprising performance in pre-season testing.
Alfa notched up a remarkable 422 laps in Bahrain, the most of any team save for AlphaTauri whose tally equaled the Hinwil squad's mileage.
But Russell, who expects to battle once again with Alfa and Haas drivers this season, especially took note of Kimi Raikkonen's fourth fastest lap overall, a performance that may indicate a significant step forward enjoyed by the Swiss team this year following a difficult campaign in 2020.
"Kimi looked very, very fast," admitted Russell. "I have to give him credit. Although I need to look deeper into the data, I would say at the moment they look like the most surprising team.
"I can't honestly tell you where I think we are in comparison, but on the face of things, Kimi looked very fast."
Alfa Romeo unveiled a fresh look for its 2021 car last month, but the team's charger also features a revised front end, with a slimmer nose compared to its C39 predecessor, while Ferrari has supplied its new and improved power unit.
Antonio Giovinazzi, who will undertake this year his third full season with Alfa Romeo, reckons the team has produced a better car this year.
"The new regulations and the new tyres aim to reduce performance, but I have to say that I have seen a lot of progress," he explained.
"The front of the car is more responsive, especially in the low-speed sections, and in general the feeling is positive in all types of corners.
"The power unit has improved too. It was an immediate sensation, and this will undoubtedly give us a hand to get closer to our rivals."
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