Lewis Hamilton stayed on top of the times in second practice for the Brazilian Grand Prix as Mercedes dominated the running.
Hamilton, quickest in the morning, posted a 1:12.271 to finish ahead of Mercedes teammate Nico Rosberg by just 0.030 seconds in a session that stay dry, despite the fear of rain earlier in the day.
Surprisingly, Williams emerged as the main challenger to Mercedes, with Valtteri Bottas and Felipe Massa in third and fourth.
Red Bull drivers Daniel Ricciardo and Max Verstappen had to settle for fifth and sixth, over half a second off the pace.
Teammate Fernando Alonso also had his running cut short after suffering an ERS problem that forced him to park his car with over half an hour left on the clock. The Spaniard was still 11th fastest.
With the threat of rain later in the session, teams were quick to start work on long runs, the hard tyres making an early appearance with the Ferrari of Raikkonen, who set the pace at the start before being relegated by his teammate Vettel, on medium tyres.
Ricciardo quickly took P1 with a 1:13.748, the Australian also on medium rubber, as Sauber's Marcus Ericsson triggered the first yellow flags as he spun at Turn 8.
Verstappen made it a Red Bull 1-2 at the 14-minute mark, the Dutchman falling a tenth short on his teammate's best as Rosberg moved up to fourth, also running on medium tyres.
Rosberg put Mercedes back on top in the same run, before Hamilton relegated him to second with a 1:13.157 on a new set of medium rubber.
Ricciardo was the first driver to complete a run on softs 20 minutes into the session, the Australian hitting the front with a 1:12.828.
Raikkonen moved to second, also with softs, before the race stewards announced an investigation into an incident involving the Finn and Toro Rosso's Carlos Sainz earlier on.
The Ferrari driver had overtaken the Spaniard around the outside of the final corner, before cutting in front of his rival to drive into the pitlane.
With an hour left on the clock, local hero Massa went quickest in the Williams, the Brazilian using a new set of soft tyres for his run.
Moments later, however, he was outpaced by teammate Bottas by 0.028s.
Rosberg put an end to the Williams hegemony with 54 minutes to go, the championship leader going half a second quicker than Bottas.
But Hamilton regained the top spot just seconds later, bettering his teammate's best by 0.030s with a 1:12.271.
Later on, as Jenson Button reported "three red lights" on the dashboard of his McLaren, teammate Fernando Alonso suffered bigger problems, the Spaniard having to park his car with 34 minutes left.
"We have an ERS problem," Alonso was told on the radio as McLaren's mechanics started work on checking Button's car.
The two-time champion got out of the car minutes later, however, calling it a day after completing only 19 laps.
|5||Daniel Ricciardo||Red Bull||TAG||43||1'12.828||0.557|
|6||Max Verstappen||Red Bull||TAG||45||1'12.928||0.657|
|9||Nico Hulkenberg||Force India||Mercedes||42||1'13.299||1.028|
|12||Daniil Kvyat||Toro Rosso||Ferrari||46||1'13.689||1.418|
|13||Carlos Sainz Jr.||Toro Rosso||Ferrari||47||1'13.801||1.530|
|14||Sergio Perez||Force India||Mercedes||38||1'13.918||1.647|