Aston Martin's Lance Stroll will have a three-place grid drop for next weekend's Mexican Formula One Grand Prix after causing a high-speed collision with Alpine's Fernando Alonso at the U.S. race in Austin on Sunday.
The Canadian and double world champion Alonso, who will be team mates at Aston Martin next season, provided one of the race's big moments on lap 22 when the Spaniard attempted to overtake on the straight.
The Alpine hit the back of Stroll's car, flying into the air and hitting the barrier, after the Canadian jinked as he tried to defend.
Stroll crashed into the wall and retired on the spot, with Alonso nursing his damaged car back to the pits as the safety car was deployed. He then returned and finished a remarkable seventh.
"It was clear to us that the driver of Car 18 (Stroll) made a late move in reacting to the overtaking attempt by the driver of Car 14 (Alonso) by moving to the left," stewards said in a statement.
"The stewards determine that the driver of Car 18 was predominantly to blame."
Stroll was also handed two penalty points, taking his total for the year to five.
"There was a big difference in speed and I was defending. I gave him plenty of room on the left of the track, so it was not as if I squeezed him against the wall," the Canadian said in his defence.
"He could have moved earlier or moved more to the left. Thankfully, it was not a big impact with the wall, I did not hit anything hard, and I am OK after the contact."