Hamilton heads Vettel in treacherous FP3

Lewis Hamilton set the fastest time of a treacherous final practice session for the United States Grand Prix which could decide Sunday's grid.

Despite the Circuit of the Americas closing the circuit to spectators until midday local time due to torrential rain, high winds and local flooding, FP3 managed to take place on schedule at 10am. With further bad weather forecast for the afternoon, teams were aware the standings from the final session could dictate the grid positions in qualifying fails to take place.

As a result, a busy session followed with cars immediately attempting to run on the full wet tyre. With the rain rarely abating, the FIA ruled teams were not allowed to use the intermediate tyre at any stage during the session.

Hamilton was actually one of the first drivers to go off track in the difficult conditions. Having run wide in the first sector on his first run, Hamilton then returned later in the session to post the fastest time with a 1:59.517. In becoming the only man to drop below the two minute mark, Hamilton also toppled the two Ferraris from the top of the times.

Sebastian Vettel ended the session second fastest having been quickest throughout the first half hour, but when the German attempted to improve later on he found the conditions too difficult. Vettel first aquaplaned at Turn 19 and ended up on the grass, before spinning at Turn 9 on the next lap and having to let the car roll backwards downhill before he could safely rejoin.

The two Ferraris appeared to have missed the best window for running, allowing a number of drivers to push Kimi Raikkonen down from second place to finish FP3 in seventh. Nico Hulkenberg completed a number of runs to end up third fastest ahead of Valtteri Bottas, Carlos Sainz and Daniil Kvyat. If qualifying does not take place, all will benefit from Vettel and Raikkonen each having ten-place grid penalties due to an engine change.

Daniel Ricciardo was eighth having been the first driver to venture out at the start of the session, with Nico Rosberg ending a tough final practice in ninth. Rosberg had a spin at Turn 7 before then going off at high-speed at Turn 3, wiping off his front wing against the barrier.

Felipe Massa rounded out the top ten ahead of Sergio Perez and Romain Grosjean, with all 20 drivers heading out to try and set times in case the session counts towards the grid.

Both Manor drivers showed good pace in the wet to outqualify Felipe Nasr and Max Verstappen, with the Toro Rosso driver going off on numerous occasions and spinning at the end of the lap. Will Stevens beat Manor team-mate Alexander Rossi by just 0.2s but was also within 0.1s of edging ahead of Jenson Button's McLaren.

Qualifying is currently scheduled to take place at 13:00 local time, with further heavy rain forecast to hit the circuit throughout the day.