Vettel still ahead as Hamilton puts up a challenge

F1 Grand Prix, GP United States, Circuit of The Americas

Sebastian Vettel now also finished the third free practice session on top, albeit not in a similarly dominant fashion as was the case on Friday. Lewis Hamilton was second quickest although less than 3 tenths behind the Red Bull. Pastor Maldonado was third, Fernando Alonso fourth.

Kamui Kobayashi was the first man out on track, soon followed by his Sauber F1 teammate and others. As usual, everyone comes back in after a single lap for system checks, to return a few minutes later for more running.

The first representative times come from Rosberg and then Schumacher 10 minutes into the session. Around that time, Pérez also has a small collision with Pic and has to return to the pits for a new front wing. No further damage was done in the incident at turn 7, where the Sauber driver passed the Marussia and then shut the door a little bit too early.

At the halfway mark, McLaren have come on top of the timesheets, with Button and Hamilton closely matched. Vettel is half a second down with the third quickest time, closely followed by Mark Webber. Neither of the Ferrari cars have set a time yet, although they jointly completed 20 laps in the first half of the session.

36 minutes into the session, Jean-Eric Vergne slides off the track and comes to a standstill in the run-off of turn 7. Both the car's front wheels point in strange directions, caused by a mechanical failure or hitting a bump a little too hard. The event also ruined several flying laps, including one of the first attempts from the Ferrari drivers.

9 minutes later, with just 15 minutes left on the clock, the Toro Rosso is removed and the track is green flagged again. By that time most drivers were sat in the pits and change to medium tyres for the final few laps in FP3.

5 minutes later, literally everyone is out on track, except for Romain Grosjean. He gets out of the car while engineers look into an apparent issue.

Three minutes from end it seems the medium tyre are getting up to temperature after 2 warm-up laps. Massa moved up to 3rd while Maldonado and Alonso post competitive first sector times. Vettel however is faster still, with purple times in S1 and S2.

Vettel's time is a full second quicker than Hamilton's best, although that was on the harder tyre, half an hour ago. The McLaren driver's only attempt on medium was right at the end, ending up in second spot, 0.3s behind Vettel. Maldonado is third while Alonso is fourth, thanks to a single lap the worked out on his final stint. Two other attempts were rendered useless as he went off in turn 19.