Mercedes reveals F1 pitstop error led to Bottas/Verstappen clash

Mercedes reacted to an early safety car by planning a double-stacked pitstop for Hamilton and Bottas, which meant the latter backed off to give himself a gap and to delay Verstappen and Sebastian Vettel behind him.

But Mercedes strategy director James Vowles has revealed that as Hamilton left the pits he hit an airgun and the recovery of the device trigged a slight delay for Bottas.

"If you can stop under a safety car in Monaco, it really is the best of all worlds," said Vowles in a team video.

"From lap 11 we knew we could take the tyres to the end of the race, we believed [it could be done on] the medium, but the hard would've easily made it as well and our competitors Vettel and Verstappen knew this too. That's why they came in.

"When you come in for a double stack safety car [stop], what's really important is making a gap between your cars so that the first car can be serviced in the pitlane and the second one can slot straight in. And Valtteri did that perfectly on track.

"Lewis had his pitstop, drove out, and you would've seen Valtteri came straight back in again.

"And now it's a straight race between Vettel, Verstappen and Valtteri for a pit stop.

"Unfortunately, as Lewis left, he clipped one of the guns and it took just a few seconds for them to reset properly and the cost to us was a couple of tenths. That's it, but that's all you need."

When Bottas left the pits, Verstappen was narrowly ahead and the two made contact.

Bottas's Mercedes clipped the pitwall and Verstappen received a penalty for an unsafe release.

Mercedes has since revealed an image of the right-front wheel that Bottas damaged, leading to a loss of pressure that was detected on the outlap.

Bottas returned to the pitlane for new tyres on the following lap and lost just one position to Vettel.

"We had a couple of tenths [time] loss on Valtteri's pit stop, Red Bull had a very, very good pitstop, one of the best of the year for them," said Vowles.

"And those extremes meant that as the cars went out and were in the pit lane, Verstappen came alongside, hit the left-hand side of Valtteri's car, pushing the right-hand side into the wall and damaging that front-right wheel, which is what you can see in this picture.

"Now, this image is obviously post-race, live we can see tyre pressures and we had a quick look at them to see what was going on.

"And after a few corners, when Valtteri was back out on the track, it became evident that we had a problem and we were starting to lose pressure.

"We had to react then and there to bring Valtteri straight back in. If we waited any longer, Valtteri would've been last.

"We brought Valtteri back in the pit lane, fitted the hard tyre, which was the best of the tyres not known at the time, and then he re-joined back in P4."