Shovlin: Perez squashed Mercedes' two-stop option in France

Mercedes engineering director Andrew Shovlin says the team's opportunity to switch to a two-stop option in the French Grand Prix was sidetracked by Red Bull's Sergio Perez.

Mercedes conceded in France another defeat to its Red Bull rival which cleverly exploited a two-stop strategy that allowed Max Verstappen to beat Lewis Hamilton to the checkered flag, although just nearly.

Verstappen had undercut the Briton earlier in the race, but much to Mercedes' surprise, Red Bull opted to pit the Dutchman a second time from the lead, a decision that proved successful.

After the race, there was much debate in the Brackley squad about why the team had not switched its own drivers to a two-stop stopper, with Valtteri Bottas calling out his crew during the race for not changing its strategy.

But in Mercedes' post-race Q&A on its YouTube channel, Shovlin justified the team's decision by Perez's all-important buffer role for Red Bull.

"In terms of the conversations during the race, with Lewis, the big issue for him on converting to a two-stop was where Sergio Perez was on track," explained Mercedes' engineering director.

"He had been able to do a much longer first stint, he was on fresh tyres and Lewis would have needed to overtake him. They [Red Bull] did have a speed advantage, his tyres would have still been in pretty good shape and we were worried we would lose a bit of time trying to do that.

"Now, as you saw with Max, he made the two-stop work. But crucially, when he came up to Sergio he just moved aside and let him through and that isn’t a luxury Lewis would have had."

• Read also: Red Bull 'quite brave' to go for second stop while leading - Brawn

Bottas' expletive-laden radio message to his team left no doubt about where he felt Mercedes had lost the race.

But Shovlin detailed why the Finn was wrong in assuming that a two-stopper would have yielded a better result.

"In Valtteri’s case, well, the big problem was that, again, because Sergio had been able to offset that first stint, if we had stopped Valtteri when he asked to convert to two, his tyres would only have been about five laps newer than Sergio’s.

"The other thing was that Sergio was on the hard tyre, Valtteri was on the medium and that was not as quick.

"So the big concern there was that we would have converted Valtteri’s strategy, taken him out of that third place, dropped him into fourth and there wouldn’t have been a tyre life difference for him to be able to attack and pass and again like Lewis.

"He would have had to deal with that straight-line speed advantage the Red Bull held."

Shovlin pointed to the level of tyre degradation suffered by Mercedes' drivers during their first stint, which led to an early stop, as the main reason why the team's one-stop strategy proved unsuccessful.

"It’s more that with the vibration, we triggered the early pit-stops that meant the one-stop was quite a difficult strategy to carry out," he added.

"It’s possible we could have instructed the drivers to do a bit more management. That might have meant we were in a better situation end of race and obviously we thought Lewis was safe [from the undercut] with that 3.2 second gap.

"It turned out it wasn’t and if we had known that, we would have stopped him the lap after Valtteri.

"Those are really the key areas where we look to perform better in the future, rather than that simple question of should we have converted to a two-stop."

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