McLaren’s Carlos Sainz branded the team’s performance during Formula 1’s Mexican Grand Prix a “big surprise” and hopes it will prove to be a one-off.

Sainz looked on course to lead another ‘best of the rest’ finish for McLaren after a brilliant start led to both drivers running inside the top five.

But McLaren’s race fell apart after a slow pit stop ruined Lando Norris’ race, while Sainz’s encouraging early pace faded dramatically once he switched onto Hard tyres. He ultimately finished 13th at the flag.

“It looked like it’d be a promising one, but unfortunately as soon as we went on the Hard and has to push to overtake the Toro Rosso’s I lost a lot of grip at the rear,” the Spaniard explained.

“I had no confidence whatsoever, and we were just sliding around on a Hard tyre being very slow, being overtaken, losing grip, and a snowball effect that meant we went backwards and had to pit again.

“It was a big surprise as we’ve been very strong all weekend and we have a chance that we get at the start to fight with the top guys we did it.

“We had good tyre management with the Softs, longer than anyone else, but on the Hards we had no grip, I hope it’s a one-off.”

McLaren team principal Andreas Seidl said the Woking squad will analyse its performance in a bid to understand why it struggled more than expected.

“We didn’t expect to be that slow,” Seidl conceded.

“First of all, especially on the Hard tyres, we didn’t have the pace we have seen in the last two days with the car.

“It is something we need to analyse and understand; if it was related to track temperatures being higher today or something else.

“Then obviously after having good starts with both cars, having the pit stop issue on Lando’s car destroyed his race and his race was over,” he added.

“We later on decided to stop his car since we are running several parameters of the cat at the limit and we didn’t want to risk any damages.

“Going away from here, I think we can be lucky that we didn’t lose any more points in the constructors’ championship because the top six cars finished and points behind were well distributed between teams.

“A day like this is part of the process for our team to become a better team.

“Lots of opportunities to learn from and simply it was a reminded that we still have a lot of work to do to become a better team.”

McLaren's first non-score since Belgium, combined with a double points finish for midfield rivals Renault, has seen the Woking squad's advantage in fourth place in the constructors' reduced to 38 points with three races to go.