Mercedes: Stacked F1 Chinese GP pitstop was Toto Wolff's idea

A strategy headache had been caused by Red Bull pitting Max Verstappen for the second time and raising the possibility of Verstappen undercutting the leading cars.

With Ferrari's Sebastian Vettel responding to Verstappen's move by pitting, Mercedes had to cover off Vettel as its two cars were leading.

But with Hamilton and Bottas in close proximity, Mercedes could not pit Bottas first and head off Vettel because it created the risk of the Ferrari driver passing Hamilton.

Wolff then suggested the stacked pitstop, which was then verified as possible by team strategist James Vowles before sporting director Ron Meadows agreed to the plan.

Speaking on Mercedes' regular post-race YouTube debrief, the team's trackside engineering director Andrew Shovlin said: "It was actually Toto who suggested that we do a stacked stop.

"That then becomes a discussion between James Vowles and Ron Meadows.

"Ron is the sporting director and he is just checking that he is comfortable with the gap between the cars, that we can get the pit crew ready to do the stacked stop and have both sets of tyres in the pit lane.

"James is the one who gets the final decision on this and he decides to go ahead with it."

Shovlin said that the risks associated with a pitstop is increased by the fact it is not easily practised.

"You don't have two cars to practice with," he explained. "We do have a pitstop car and we can practice getting both sets of tyres out, we can practice doing two stops in succession but you can never quite get the same situation with the car rolling into the box.

"It is quite difficult for the rear-jackman as he has to get out of the way when the first car leaves and then get into position when the second one comes in.

"The choreography is quite tricky, there is a bit more to organise. Having that many tyres in the pit lane is a bit of a risk, so you have to make sure the right tyres go on the right car. But it is something we do as much preparation for as we can."

He added: "You try not to do them unless you have to because if you have any problem with the first car, it also impacts the second - and you can go from being first and second in the race to third and fourth in no time.

"It isn't something you do every day, but on the occasions it makes sense it is a really [useful] tool to have."

Bottas's pitstop proved to be quicker than Hamilton's and he lost less than half a second compared to his team-mate despite waiting for his team-mate to finish his stop first.