Mercedes broke own pitstop record in Chinese GP

The move to bigger wheels and tyres as part of the 2017 rule package slowed pitstops from the start of last season.

However, in Shanghai, Mercedes demonstrated that is now back where it was in 2016, despite problems with unsafe releases up and down the pitlane leading to some teams taking a slightly more cautious approach.

In China, Bottas went for the undercut on Vettel when he came in on lap 19, and he successfully jumped the Ferrari driver, who pitted a lap later.

The official stop time for the Finn was 2.15s – winning the DHL Fastest Pitstop award – but Mercedes says that by its own internal measure, the stop was even quicker.

"We were 3.3s behind Sebastian when we came into the pit lane in order to execute the undercut," said chief strategist James Vowles in a Mercedes video.

"A few things came towards us perfectly all together at the same time.

"The first was that our pitstop was incredible. In this new era we did a 1.83s time, based on our traffic light system. That's very quick, since Austin 2016 with the smaller wheels and tyres, we haven't done times around that.

"And Sebastian's stop was round about 0.9s slower, if you measure across the pitlane time, and the pit stop was around 0.7s of that. So already straight away you've eaten into his margin."

Vowles stressed that Bottas also made a big contribution to the successful pass.

"Valtteri's out-lap was extraordinary. We have a number of messages we gave to Valtteri, to make sure he knew what he needed to do, and it was like a qualifying lap, he executed it perfectly, he didn't make any mistakes.

"That then contributed to a couple of seconds gained.

"The final element is on the in-lap you can see Sebastian really struggling on those old soft tyres. They were still in a good state, they weren't completely gone, but you can see a few tenths' loss for them on the way in as well.

"All of that came together beautifully to allow Valtteri to come out around 0.7s ahead of Sebastian. It was an undercut, it was a pitstop coming together at the same time, and it was a fantastic out-lap from Valtteri."