A determined Lewis Hamilton completed a perfect record-breaking 'double top' in Friday's practice for this weekend's Brazilian Grand Prix, leading his Mercedes team-mate Valtteri Bottas in both sessions.
The 32-year-old Briton, who clinched his fourth world championship in Mexico two weeks ago, dominated the day and showed no signs of easing off — or any reaction to the controversy about his alleged tax avoidance.
He and Bottas were fastest in the morning's opening session and followed up with repeat performance in the afternoon, Hamilton clocking a best lap in one minute and 9.515 seconds to outpace his team-mate by 0.048 seconds.
"There are still two races to go," said Hamilton.
"I am still in the same mental frame of mind that there are still races to be ticked off and it wouldn't feel normal to back off now.
"It's the best time ever to apply even more pressure — just because I can. There are still two wins available."
Hamilton's earlier quickest lap in the morning was in 1:09.202, a clear margin faster than the qualifying lap record of 1:09.822 set in 2004 by Rubens Barrichello of Ferrari.
Wearing a repainted helmet sporting four prominent stars to mark his world championship triumphs, Hamilton appeared unaffected by the cold he developed during a trek of Machu Picchu in Peru as he set to work as usual.
In a session run in dry, hot, but cloudy conditions ahead of forecast rain, Mercedes led the way as they tested new parts and systems for 2018, the two drivers' form suggesting no let-up in pace.
Australian Daniel Ricciardo was third for Red Bull, his car also running a clutch of new items, ahead of four-time champion Sebastian Vettel of Ferrari, Mexico victor Max Verstappen in the second Red Bull and Kimi Raikkonen in the second Ferrari.
Vettel admitted he and Ferrari had been outpaced in practice.
"Mercedes look very strong," he said. "Both of them are a bit ahead of us, but I think it is very close between us and Red Bull.
"I hope we can find a nice balance in the car on Saturday and see what we can do. In general, it is nice to be out in the car again. I like driving — and it is quieter on the track here than it is off it."
Esteban Ocon was seventh for Force India ahead of retirement-bound local hero Felipe Massa, in his final home race with Williams, Nico Hulkenberg of Renault and two-time champion Fernando Alonso of McLaren Honda.
Hamilton said earlier Friday that he was happy to obey team orders, if required, to assist Bottas in the final two races of the season as he bids to overhaul Vettel and take the runners-up spot. He is currently 15 points behind him.
Ricciardo is expected to be hit with a grid penalty for a change of his car's Renault power unit along with New Zealand rookie Brendon Hartley and his Toro Rosso team-mate Pierre Gasly, who both have penalties for engine changes.
On his 28th birthday, and a week after winning the world endurance championship for a second time, Hartley had mixed fortunes.
He failed to clock a time in the morning and was 17th in the afternoon, one place behind fellow-rookie Galsy.
The session saw few incidents, but Marcus Ericsson brushed the barriers in his Sauber, Stoffel Vandoorne of McLaren survived a spin at the Senna 'S' curve and Romain Grosjean spun and recovered in his Haas on the back straight.