Mercedes technical director James Allison has outlined the vital pre-race strategy call that played a pivotal role in Lewis Hamilton’s Bahrain Grand Prix victory.

In the build-up to the race, Mercedes opted not to use any of its two available sets of the hard tyre throughout practice or qualifying, conducting the majority of its running on the soft Pirelli compound.

Given the high level of thermal degradation around the Bahrain International Circuit, this proved crucial as it allowed Mercedes to run its second and third stints on the hard tyre after starting the race on the medium.

In contrast, with only one set of the hard tyres available that was used for the final third of the race, Red Bull opted to race the medium across its first two stints.

While Red Bull appeared to have the edge as they had the quicker car and were using the medium tyres for two stints, this actually played into Mercedes hands.

Explaining it was “a finely balanced decision”, Allison said: “It’s not like one of them is a no-brainer, the other one a completely moronic choice.

“Each one has a slight advantage over the other in certain circumstances. So, the medium tyre, all things being equal, will be slightly faster over a certain number of laps, but it will die sooner

“The hard tyre is just a whisker slower but it will be fairly bulletproof for a large number of laps. So, those two different characteristics give you different options.

“We judged, and you have to remember we were only at this track a few months ago in 2020, that the pace difference between the hard and the medium was going to be sufficiently small that we valued the increased life a little higher than we valued that shade of extra pace that the medium tyre gave you.

“And we intended to use that extra life to put ourselves in a position where we could be brave at the point where we did our stops.”

Mercedes blinked first

From a position of strength, as Hamilton had managed to keep within two seconds of Verstappen over the first stint, the seven-time F1 champion pitted first.

Allison added: “We know in Bahrain it is one of the tracks that has the most powerful undercuts.

“You need only to get within about two seconds of the car ahead, and if you stop one lap sooner than you can jump past using an undercut.

“Now, if you know that what you have got tucked up in the garage is a nice set of unused hard tyres and you know that set can go deep, deep into the race then it gives you the confidence to make that undercut move, to dive in the pits and stop really quite early in the race, and to hopefully use that undercut to jump past.

“If you are sitting on a medium tyre with someone hard up behind you and you are worried that they are going to undercut you, but all you know is you’ve got mediums in the garage, then you are nervous about diving in the pits too early in the race because you know that your tyres, maybe, are going to struggle if they have to run too long a stint.

“So, we placed the value on the stint length and it was that we then used in the race, admittedly in quite an extreme way, to make sure that we used the length of the stint to our advantage.

“It was that that allowed us to first undercut and then protect against an undercut having seized the lead with that very, very aggressive early stop and long final stint that Lewis did to hold on for the win.

“So, it is a matter of taste, a matter of choice but we chose it for those reasons and then we exploited that opportunity to sneak a win in a very, very closely fought race.”