Formula One: Rain causes havoc in Japan free practice

The Briton, who suffered his first race retirement in over a year in Singapore last week, clocked the fifth fastest lap of one minute, 1:50.722 seconds, a shade slower than Mercedes team mate Nico Rosberg and Ferrari's Sebastian Vettel.

Rosberg timed 1:50.077 and fellow German Vettel -- who won in Singapore -- 1:50.519.

Toro Rosso's Carlos Sainz Jr topped the timesheets in 1:49.434, the Spaniard half a second clear of Red Bull's Daniil Kvyat in a hair-raising morning session.

With memories of Frenchman Jules Bianchi's fatal crash at a wet Suzuka last year set to make Sunday's race an emotional one, drivers were anxious to avoid taking any risks in the treacherous conditions.

Hamilton, who leads the title race by 41 points with six races left, ventured back out to set his first timed lap with 12 minutes to go after several of his rivals complained about aqua-planing over their team radios.

With spray from a soaking track making the going dicey in heavy rain, cars limped around on wet tyres until the weather offered a brief window for a mad dash to set times on intermediates towards the end of the session.

Vettel struggled to correct a heart-stopping slide through the quick right-hander between the hairpin and Spoon, while Rosberg also survived a couple of scares, braking late into the chicane and sliding onto the run-off.

Felipe Massa expressed his reservations after his Williams slid into the gravel approaching the hairpin, while Kvyat's seemingly reasonable query about his brakes not working was met by a terse: "Try to be more positive!"

Finland's Valtteri Bottas summed up the gloom when asked by his Williams team: "Let me know if you want to continue if it's safe." Bottas shot back: "No, it's terrible" -- to which the team Finn replied, "copy, box," to call him into the pits.