SUZUKA (AFP) - Mercedes pair Lewis Hamilton and Nico Rosberg showed flashes of pace in Friday's second free practice in Japan before heavy rain effectively washed out much of the afternoon session.
Red Bull's Daniil Kvyat topped the timesheets at a soaking Suzuka, clocking one minute, 48.277 seconds, with Rosberg 0.023 back and reigning world champion Hamilton a further half a second slower.
Rain had created havoc in the morning practice, when only 12 drivers completed a timed lap as they struggled to keep control of their aquaplaning cars.
Mercedes, looking to fix a mysterious loss of pace in Singapore last weekend, shot out to the quickest times in the second session, before Kvyat backed up an impressive early display by edging ahead of Rosberg.
But, just as things began hotting up, the rain returned to send the cars back to their garages and, when Hamilton finally emerged on wet tyres, he was warned over the radio "be mindful of the rivers",- so soggy were the conditions.
Daniel Ricciardo clocked the fourth fastest time behind Hamilton with Singapore winner Sebastian Vettel steering his Ferrari to the fifth-quickest time.