Ferrari have elected to change Sebastian Vettel’s chassis after the German experienced problems in Friday’s second practice session in Austin.

Having been late to go out on track in FP2 as Ferrari made changes to his car following first practice, Vettel then had a huge slide off the road at Turn 19 and spent some time in the pits before re-emerging.

The four-time world champion was third fastest after completing his run on the ultrasoft rubber, but he soon returned to the pits complaining that something ‘felt weird with the front axle’ and ultimately clocked just 11 laps.

“It was a complicated afternoon and not an easy session” said Vettel, “but the car is quick, so we don’t need to worry too much about it.

“The only lap I had was the one with the ultrasofts. Before that, I made a mistake taking too much risk and pushing too early.

“The track was quite slippery and I lost the rear under braking. So, we lost a set of tyres, and then again, towards the end of the session, I felt that something was not right with the car.

“So, we checked a couple of times and now we are looking at the car to see if we can find something.

“I need to find the rhythm tomorrow and make sure everything’s in order.”

Vettel came into the weekend trailing Lewis Hamilton by 59 points in the drivers’ standings with four races remaining.

If Hamilton were to win on Sunday, Vettel would have to finish fifth or higher to prevent the Briton from joining him in becoming a four-time world champion.

The German's car will be re-scrutineered ahead of final practice on Saturday morning.