Lewis Hamilton showed no ill effects from his fever during first practice for the Brazilian Grand Prix as he topped the session by over half a second from team-mate Nico Rosberg.
Hamilton flew to Brazil a day later than planned after recovering from a fever and being involved in a minor car crash, but he was back on top form as soon as he returned to the track on Friday morning. Mercedes was testing a number of aerodynamic tweaks on its cars, meaning times may have been influenced by differing run plans, but Hamilton was still 0.519s clear of Rosberg by the end of the session -- a significant margin over such a short lap.
Sebastian Vettel was third fastest in the Ferrari and 0.625s off Hamilton's pace, while Red Bull's Daniel Ricciardo was fourth fastest and another 0.281s down the order as he ran Renault's upgraded power unit for the first time the year. The Red Bull split the two Ferraris as Kimi Raikkonen finished over a second off Hamilton after completing fewer laps than any other driver in the 90-minute session.
Raikkonen stayed in the garage for much of the early part of the session and after 30 minutes of running he had yet to set a time. At one stage he was as high as third fastest, but his session ended early following a spin at Turn 4. Raikkonen lost the rear of his car under braking, touched the grass on the outside and then spun off through the gravel. He gingerly returned to the pits before Ferrari called it quits after another short run.
Valtteri Bottas was the highest-placed Williams driver in seventh behind Daniil Kvyat and ahead of Max Verstappen, who also had a spin early in the session. Nico Hulkenberg and Pastor Maldonado finished ninth and tenth ahead of Carlos Sainz and Jolyon Palmer -- the latter standing in for Romain Grosjean in the morning session as part of his ongoing preparations for a race drive at Lotus next year.
Jenson Button was the highest-placed McLaren driver in 13th, 1.8s off the pace of the lead Mercedes and 0.034s quicker than team-mate Fernando Alonso.