Montmel (Spain), Feb 29: Valtteri Bottas took his Mercedes to the top of the time charts once again on the final day of pre-season Formula One testing but teammate and world champion Lewis Hamilton warned performances were "not perfect".
Two weeks out from the season-opener in Melbourne, Bottas, runner-up to Hamilton in the world championship in 2019, clocked a best run of 1min 16.196sec off a total of 79 laps. The Finn also finished the two sessions of winter testing with the fastest overall time of 1:15.732, the only driver to dip below the 1min 16sec mark.
Red Bull's Max Verstappen and Renault's Daniel Ricciardo filled out the top three on Friday with Hamilton in fifth.
"On the whole, these tests were good but not perfect," admitted Hamilton, who this season eyes equalling the record of seven world titles held by German legend Michael Schumacher.
"We have had a lot of problems that we are trying to solve," he added in reference to the need for the team and clients Williams having to change power units after breakdowns.
"We will see how long it will take to resolve them, but it is better to discover these things in tests."
Mercedes put in most laps in Barcelona with 903 ahead of Ferrari (844) and McLaren (802).
Ferrari 'not hiding'
They also introduced the revolutionary DAS (Dual Axis Steering) system last week which had rivals scratching their heads over its potential impact in the forthcoming championship.
"Their form is good and it's better to have concerns during the tests than in the race," said Christian Horner, the boss of Red Bull.
Horner had the satisfaction of seeing Verstappen, who was third in the 2019 standings and is widely-viewed as a world champion-in-waiting, second fastest on Friday and second overall.
Ferrari, the only team not to have beaten their times of 2019 on the same circuit, were left in a cautious mood. They dominated testing 12 months ago but once they got to Australia, reality hit them hard when Bottas swept to victory, the first of eight wins for Mercedes.
Ferrari had to wait until September, the 13th race of the 2019 campaign, to win a race courtesy of Charles Leclerc. "We are not hiding," said Ferrari team chief Mattia Binotto.
"We are not yet fast enough to hope to win in Australia. But the season is long -- we will have the opportunity to improve and be ready to win."