Marquez, a seven-time winner at the Circuit of the Americas, slid out in the early stages of the session at very high speed and was dragged through the gravel.

While the initial pictures seemed very alarming with Marquez pressed into the barriers, he headed back to the Ducati garage on a scooter and appeared to have avoided serious injury.

Turn 10, one the fastest corners on the COTA circuit, doesn't have a huge amount of run off as crashes there are not very common, but coming over a crest into a sharp left-hander is inevitably a big challenge for MotoGP bikes.

We will keep you updated here on GP Blog regarding Marc's condition and further participation in the race weekend.

UPDATE: Marc returned to the spare bike and continued the session, finishing in 4th!

It was a dramatic session in FP1 at the Circuit of the Americas in Austin, Texas, as the riders got their first feel of the circuit ahead of a highly anticipated race weekend.

Check out the full results for the MotoGP USA Grand Prix FP1 session here.