While McLaren had lost the lead to Verstappen at the first safety car stop for Logan Sargeant’s stranded Williams, Horner does not think that was the key moment that opened the door for his team’s victory.
Instead, he suggests that the “crucial” decision came later in the race when drivers started moving across to the slicks and Norris elected to run longer than everyone else.
With the slicks taking a while to come up to temperature, Norris’s decision appeared to be inspired as his inters remained faster.
But his call to stick it out for two further laps did not quite work out, even though he had a 20-second advantage over Verstappen at the time.
Although he was able to emerge from the pits marginally in front of Verstappen, the exit blended on to a damp part of the track and he could not get traction – which allowed his rival running on the dry line to pass him for the lead.
Horner reckoned that things would have been different if Norris had pitted just one lap earlier, as Verstappen's tyres would not have been up to temperature.
“I thought we were in a much better window as the circuit dried out,” explained Horner.
“We were able to hold a consistent gap and then it was all about getting the crossover at the right time, because the first sector was pretty damp. When you drive out of the pitlane, you lose a huge amount of the temperature.
“I felt like we timed that about right, going onto the medium tyre. Whilst Lando was able to capitalise enough to hit the 20-second mark, and it hovered around that, with each lap we did, the tyres were getting warmer and I was surprised they didn't cover after one lap.
“They left him for two and that was crucial as that gave Max another lap to generate the temperature. When Lando did pit, he [Verstappen] had tyres that were in a window and was able to drive and pull out a three-second gap by sector one. So that timing was crucial.”
The importance of the timing of that switch to slicks came after Horner admitted McLaren had looked on course to win when Norris enjoyed a huge pace advantage on the drying track in the first stint.
“In the first stint, we looked very competitive at the beginning of the race, pushing George [Russell] very hard and pulled out seven seconds very quickly on the cars behind,” he said. “So the wetter conditions we were set-up pretty well for.
“Then unfortunately, we just dropped a little back from George as the DRS opened, which then allowed Lando to come back as the track was drying out. It looked like the Mercedes was in more trouble, but we were struggling to get past and that gave Lando a free pass.
“At that point, it looked like McLaren was the favourite to walk away and win the race. Then pitstops came and we went onto another new set of inters.
“There was a safety car that neutralised everything and the adjustments we made, we were then able to get ourselves into a better position.”
