Lance Stroll's opening pitstop disaster in the Las Vegas GP was caused by his Aston Martin Formula 1 car suffering a radio failure on lap one of the race.
The 26-year-old responded to instructions to aid his launch from 18th on the grid, but then could not communicate with his engineer Ben Michell thereafter.
This meant when he suffered with the extreme graining on the medium tyres many of his rivals also encountered, he struggled to tell Aston he needed to pit earlier than it had planned – trying to do so by repeatedly pressing his 'pit confirm' steering wheel button ahead of coming in on lap nine of 50.
But when Stroll arrived at his Aston garage there were no mechanics ready with hard tyres, with the team scrambling to service his AMR24.
The team had told him to use the pit confirm button to indicate he was having radio problems, but no instruction to pit was forthcoming on the lap he stopped in any case.
"Difficult race, no radio from lap one," Stroll told reporters. "No communication. That made it difficult with the pitstop and trying to tell them that I was coming with the pit confirm. But the message didn't go through."
When asked how much the problem had cost him in terms of race time, Stroll replied: "20 seconds – a lot.
"It's the same in the car," he added. "There's no problem from the car, it's just the strategy and the pitstops.
"I knew that the medium tyre was dying a lot at the beginning of the race and I wanted to come in and go as quickly as possible on the hard tyre.
"But then our plan was to go longer on the medium tyre before the race, but the medium was worse than we expected, so I was trying to communicate that and tell them that I was coming in earlier.
"But then it was kind of impossible to communicate other than the pit confirm. So, just one of those races."
Team principal Mike Krack said his squad eventually established it could "manage the race via the pit board" and Stroll's second stop later went off without a hitch.
Stroll, who eventually finished 15th, reckoned "P12, maybe a few [extra] positions", would have been possible if not for the radio failure.
He continued: "Because we lost 20 seconds and we finished 10 seconds behind the two drivers in front of us. So, a couple of positions there, but no points on the table."
Another driver who encountered a pitstop shambles in Vegas was Alpine's Esteban Ocon, also at the first round of stops.
He had obeyed an instruction to pit if Nico Hulkenberg – ahead for Haas – did not, but when Ocon arrived in the pitlane only a single Alpine mechanic was in his pitbox and he drove on without turning in, saying via team radio he "didn't see the board" indicating the team were waiting for him to stop.
"It's a difficult situation at the time trying to box opposite," Ocon said, with the Frenchman coming in the following lap and finally swapping his mediums for hards, but dropping from a solid 11th to only ahead of Stroll when he rejoined.
"But we eventually did a drive-through for nothing because we didn't change tyres and that cost our race because then we try and hang on for that one stop until the end."
Alpine team principal Oliver Oakes said it was "just a mistake on the team side" that caused the issue, with Ocon's failed 'one-stop' resulting in a late pit for softs and an eventual finishing position of 17th after he started 11th.
Additional reporting by Emily Selleck and Mark Mann-Bryans
