Valtteri Bottas has hailed the “big improvement” made by his Mercedes Formula 1 team ahead of qualifying for the Mexican Grand Prix.

Mercedes endured a difficult day of running on Friday and struggled to match the pace managed by the Red Bull duo, while the team also had to turn down its engines down on both cars amid overheating fears.

It’s uncharacteristic below-par practice performance led Lewis Hamilton to claim Red Bull were “out of reach” for Mercedes heading into qualifying.

But a much-improved display, aided by cooler conditions on Saturday, enabled Hamilton to qualify third and just 0.135s off pole, while Bottas recovered from an engine issue in FP3 to split the Ferrari pair in fifth.

“I think the biggest thing to talk about is the big improvement we’ve made, as a team from yesterday,” Bottas said.

“The car was a lot better, had a lot better performance than yesterday, so the team did a really good job on day.

“I think with the car we had yesterday, the highest we could have definitively been was fifth and sixth.

“What was done for today allowed for Lewis to get P3 and I was a couple tenths away. There was a big difference from yesterday, but we still needed to find a few more tenths.”

Further rain and thunderstorms are expected prior to Sunday’s race, which Bottas reckons will cause a difficult day of tyre management due to the increased grained created by ‘green’ track conditions.

“The track always re-sets with the rain, with a lot of dust. The greener the track, the more graining we get and it could be a difficult day tomorrow,” he explained.

“But we’re not the only team struggling with graining, I’m sure it will be the same for everyone. The key in the race is not to open up the graining, but here there’s a possibility for one or two stops.

“If you can avoid the graining, one stop will be possible, but if you get graining then you’ll have to do two stops.”