Daniel Ricciardo has been handed a three-place grid penalty for the Spanish GP after reversing into Daniil Kvyat in a bizarre clash in Azerbaijan.
The Australian had been attempting to pass Kvyat with DRS on the run down to Turn Three on lap 31, but went in too deep.
He locked up and had to take to the run-off zone, with Kvyat also having to stop on the corner having been unable to turn in.
But while they initially avoided contact, Ricciardo was then too quick to find reverse gear and went straight into the stationary Toro Rosso behind with Kvyat still to get his car going again.
Stewards investigated the incident and handed Ricciardo a three-place grid drop for the next race in Spain on May 12, while adding two penalty points to his hitherto clean licence.
"I don't feel good about what happened. It's weird," Ricciardo told Sky Sports F1.
"I saw a gap so thought I would have a go. Initially, I had the commitment and thought I would pull it off. But then I felt I would start to lock and missed the corner.
"As soon as I went down the escape road it was a sense of urgency and a bit of panic, I guess, and just trying to minimise damage and lose as little time as possible. I found reverse and started going and had no idea he was there. I guess the urgency stopped me from looking.
"When I went long, I assumed he would have cut back and stayed on track. Trying to minimise the mistake I made turned into another mistake."
The incident left both drivers having to retire with the damage caused, making it three DNFs in four grands prix for Ricciardo at the start of his Renault career.
Ricciardo apologised to Kvyat in the post-race interview pen.
Sky Sports F1 is the home of live and exclusive F1. Find out more here to watch the 2019 season live