Championship leader Nico Rosberg beats reigning champion Lewis Hamilton in United States GP practice. The Brit was 0.291 seconds slower than his teammate, with Red Bull's Daniel Ricciardo splitting the Mercedes.
With four rounds remaining and a total of 100 points up for grab, Rosberg doesn't seem to be slowing down. He did his fastest lap on fresh supersoft tyres.
Hamilton was fastest in the opening session in the morning, but Rosberg bounced back to top the times in Free Practice 2.
Scuderia Ferrari's pilot Sebastian Vettel was fourth quickest, ahead of Red Bull's Max Verstappen. The German was 0.820 adrift ahead of the Dutch teenager.
After the session, Vettel said, "A tough day for us. We had problems in the morning when a little wing failed and came off and we lost some track time. I think we have been on the back foot today and I'm not entirely happy with the balance of the car yet.
"It's a bit too nervous all round. I think we can improve. I think the Ferrari you saw today is not the Ferrari you will see tomorrow."
Force India driver Nico Hulkenberg finished the session in sixth, ahead of his teammate Sergio Perez. The 2009 champion Jenson Button along with Fernando Alonso claimed the eighth and ninth position, with Kimi Raikkonen completing the top 10.