Max Verstappen says his only focus is on winning the Mexican grand prix this weekend.

When asked about Sebastian Vettel's recent championship troubles and driving mistakes, the Dutchman said he is not at all interested.

"I need all my attention for my own performance," the Red Bull driver told De Telegraaf.

He also refused to say whether he thinks he would have won the 2018 title in Vettel's Ferrari.

"I do not answer that. It's totally irrelevant.

"I have come here to win, not to be on the podium. The circumstances are in my favour, so I must take advantage of that. Starting with practice and then qualifying," said Verstappen.

A technical glitch aside, practice started well for Verstappen, as he looks the driver to beat in Mexico.

"Everyone is struggling with tyres except Red Bull. They seem to have the least amount of problems," said Ferrari's Vettel.

Red Bull is also looking ahead with confidence to 2019, when it will have works Honda power.

"Our goal is to fight for the title, even if realistically it will be difficult," Dr Helmut Marko is quoted by Brazil's Globo.

Verstappen added: "Personally I do not think we will be strong at the start, but I think we will make up ground throughout the year."

To that end, Honda and Red Bull are already pushing hard, with Toro Rosso currently the 'test mule' for aggressive engine development.

"The engine we will have next year is a new project," revealed Red Bull boss Christian Horner.

Car designer Adrian Newey said: "It's been very different from receiving Renault's technical data. We are developing in partnership with Honda and can really feel the difference.

"It's something we have never been able to do with Renault," he added.