Alonso set for back of the grid start in the US Grand Prix after changing PU components

Alpine have revealed Fernando Alonso has taken a complete fresh power unit for the remainder of the United States Grand Prix weekend, which exceeds his allocation and triggers a grid penalty that will confine him to a back of the grid start.

The Spaniard had a tricky Friday, first losing a significant amount of track time after an operational issue forced him to stop out on track in FP1 (see the clip below), then spinning at the end of the second session as he struggled to get comfortable with the car.

READ MORE: 'Not a super smooth Friday for us' says Alonso after FP1 stoppage and spin into barriers in FP2

During final practice in Austin on Saturday morning, Alpine revealed the double world champion has installed a fourth internal combustion engine – drivers are only permitted three per season.

They have also taken fresh sets of all other components – turbo, MGU-H, MGU-K, energy store and control electronics.

That means he’ll join Williams’ George Russell and Aston Martin’s Sebastian Vettel at the back, after the duo were hit with penalties for changing their Mercedes power unit components.

It comes after Valtteri Bottas took a new internal combustion engine – his sixth of the season, which has incurred a five-place grid penalty for Sunday’s Grand Prix.

READ MORE: Mercedes 'trying to get on top of engine problems' as they weigh up Hamilton PU penalty