Undercut strategy that won Red Bull the 2021 French Grand Prix

Strategy becomes a whole lot simpler when you have a faster car than your opponent. Red Bull demonstrated as much in the two Austria races, but in the preceding Paul Ricard race things were rather more nuanced. The Red Bull advantage was not as clear-cut and once Lewis Hamilton had taken the lead at Turn 1 after Max Verstappen ran wide, it looked like he had the race under control. The Red Bull was not sufficiently faster that Verstappen could overtake on track and as Hamilton steadily built up a lead of over 3sec during the first stint, it was difficult to see any strategic way for Red Bull to break Hamilton’s command.

But Mercedes underestimated just how big the undercut effect could be and mistakenly believed Hamilton’s 3.1sec advantage over Verstappen before the Red Bull pitted would be enough to allow Hamilton to pit a lap later and rejoin in front. It wasn’t.

Hamilton had used up more of the front tyres by the time he came to do his in-lap than had Verstappen. By keeping out of Hamilton’s turbulence zone Verstappen ensured he still had plenty of rubber by the end of the stint. Also, this is partly a function of the car’s balance and its general performance. As Bottas observed in Austria: “If you’re further off with the car you have to push harder and the tyres suffer.” So Verstappen’s in-lap was quick. Hamilton’s in-lap was 0.9sec slower. More important, Verstappen’s out-lap was very quick. The difference between that and Hamilton’s concurrent in-lap was the big reason for the undercut working.

“My out-lap was good but I didn’t expect the undercut to be so big, but when I went out I suddenly had so much more grip. Nobody – including us – expected to undercut Lewis so it just clearly showed that with new tyres you have one lap where everything feels a lot better. As soon as I was ahead, the next two laps, they didn’t feel so great any more.”

“Verstappen was comfortably able to pass Bottas and to catch Hamilton before the end.”

Bottas had pitted the lap before Verstappen and had gained 1.1sec on him by doing so. That informed Mercedes that Hamilton’s 3.1sec gap would be enough. So why the big difference in Bottas’ gain and that of Verstappen? The Mercedes was taking a whole lap to get the hard tyre up to temperature, the Red Bull was not.

When it then became apparent that at the pace Verstappen and Hamilton were setting, even the hard tyre was going to struggle to give the stint length required to finish the race, it was a question of who would pull the plug first in converting to a two-stop – which would oblige the rival to stay with the one-stop.

Normally it’s the guy behind with nothing to lose who would be expected to do this. The leader is throwing away track position in doing it – which he might not get back. Mercedes was reluctant to make the move because Hamilton would have come out behind Pérez and would have had to find a way by him to catch Verstappen. With the Merc being down on straight-line speed to the Red Bull, this was judged too risky. It might have trapped Hamilton in fourth.

Red Bull, nervous that Mercedes was going to switch to the two-stop, anticipated it and brought Verstappen in. It was confident it could regain track position because of its straightline speed advantage – and so it proved as Verstappen was comfortably able to pass Bottas and to catch Hamilton before the end. So much more tyre grip did he have it was simple to out-brake the Mercedes into the chicane.

Was there any way Mercedes could have won it? Hamilton: “If we had stopped earlier, before they had, come out ahead, and gone onto a two-stop, we could have won – but it would have still been difficult. If he had not made a mistake in Turn 1, they might have just led the race all the way.”

Tyre tactics

With pace advantage over Lewis Hamilton in the Austrian GP, Max Verstappen was able to hold first place after a pitstop, then built up his lead in order to take a second stop without compromising his advantage. On fresh tyres Verstappen took a late fastest lap and an extra point