Horner expresses McLaren surprise after crucial Canadian GP mistake

Christian Horner was left surprised by McLaren's decision to delay Lando Norris's switch to slick tyres in the Canadian Grand Prix, believing Red Bull aced the "crucial" decision. 

As the track dried following the rain showers, the timing of the switch from intermediates to slick tyres was key, with Max Verstappen diving for the pits, along with George Russell at the end of Lap 45. 

Norris extended by two laps, coming in at the end of Lap 47, but although he exited Turn 2 in the lead, the squirming McLaren was not able to put the power down with a lack of temperature as Verstappen swept passed and was relatively untroubled thereafter, recording a 60th grand prix win. 

Norris would finish second ahead of Russell, as Horner spoke of the advantage McLaren had handed Verstappen by delaying Norris's stop.

"The pit-stops [for fresh intermediates] came and we went onto another new set of inters, and with the safety car to neutralise everything, we made adjustments to get ourselves into a better position as we were set-up for wet conditions," Horner told media including RacingNews365.

"Then it was all about getting that cross-over [to slicks] at the right time, because the first sector was pretty damp when you drove out of the pit-lane, and you obviously lose a lot in temperature.

"We timed going to the medium tyre about right, and whilst Lando was able to capitalise enough to extend the gap to 22 seconds, obviously each lap we did with the [slick] tyres getting warmer, I was surprised they didn't cover after one lap, and left him out for two. 

"That was crucial as it gave Max another lap to generate temperature, so when Lando did pit, Max had the tyres in the window and was able to drive straight past and pull out a three-second gap by the end of sector one - so that timing was crucial."

It was the second time during the race that Norris went a lap longer than Verstappen or Russell, with the first being during the safety car for Logan Sargeant's Lap 25 crash. 

The Red Bull and Mercedes, nearly seven seconds behind Norris when the safety car was deployed, were able to pit whilst Norris did another tour - and collected the safety car at Turn 5. 

McLaren adjudged the fine margins as to why it could not pit Norris, but Horner felt certain McLaren could have been more proactive when pitting. 

This delay for Norris cycled Verstappen to the lead - something he'd only lose again during the two laps Norris led during the second pit-stop cycle for the change to slicks.

"We would have come in as the tyres were toast and we knew the rain was coming," Horner explained of the pit-stop under the Sargeant safety car.

"All the information was that the rain was coming so we were surprised that they didn't prempt it to be honest, as it looked like it was going to be a safety car.

"But it is kind of payback, and I think Gianpiero Lambiase made the comment, which I felt was 40 laps too soon, that it was the way that safety cars go and it was pay back for Miami."