Lewis Hamilton has revealed that he sacrificed his time in the Mercedes W09 on Tuesday in order that teammate Valtteri Bottas could have more running in the auto. Ahead of the lunch break the sun warmed the track and enabled more meaningful running, but Mercedes was due to switch its single vehicle between Bottas and Hamilton at that time - a procedure that requires the seat and pedals to be switched and takes up to an hour.
The German ace clocked 1:19.673, beating last year's record set by Mercedes' Valtteri Bottas.
"It's way too early to say but if I would have to guess something I would say it's definitely going to be closer", Bottas told reporters.
Nico Rosberg admitted that he put a lot of effort into trying to get under Hamilton's skin as part of his strategy to defeat his then-teammate, before retiring after becoming world champion in 2016. That's what I believe.
But Mercedes announced after the lunch break was cancelled that Bottas would continue behind the wheel "to maximize our mileage after the poor track conditions limited running this morning".
"They have the experience, I don't know how many races they have (between them)".
"We need to see how the next few hours evolve and come back and have the conversation about it".
American team Haas F1 used Magnussen for the day, and the Dane had a awful time, almost striking the barriers at turn 4, and conducting limited mileage that he could not change until the team made limited modifications to the vehicle.
"(Mercedes executive director) Toto Wolff wants us both to be performing on a 100 per cent level, and that can provide some healthy competition".
"This is a big year", McLaren's American chief Zak Brown said.
Asked if McLaren could make it a four-team fight, Bottas replied: "As a team we don't underestimate any team or driver".
Fernando Alonso was the first driver to emerge from his garage as he completed one lap in his McLaren before returning to the pits.
"It was a very, very small problem, but very graphic and very obvious because a auto in the gravel is a big thing", Alonso said.
Mercedes, Ferrari and Red Bull appear at this early stage to have the three fastest cars - as they did past year - while Renault, who were the next quickest team on Tuesday, as they were on Monday, are also looking promising.