Jenson Button insists there is “no room for error” ahead of a “very fast” Saudi Grand Prix.
The Briton is now eight points clear of the Belgian-Dutch driver, who is aiming to deny the Mercedes star a record-breaking eighth world title.
And Button, a world champion in 2009, has called the state of the title race, warning both drivers there will be no margin for mistakes with just two races remaining.
“It’s extremely tight, and we don’t know which car is going to be quick at the next race [at the Jeddah Street Circuit].
“It’s an exciting track from what we’ve seen. It’s very fast, no room for error in Saudi Arabia, with all the barriers around the track which makes it even better.”
Button was then pushed to predict a winner but refused to side with either man, suggesting the layout of the Abu Dhabi track could settle this year’s title race.
“I’m still not going to get off the fence, and that’s why it’s awesome. I actually have no idea, both are doing a great job, teams are doing a great job,” Button added.
“It looks like Mercedes has the upper hand at the moment, but the next circuit is very different. And then obviously Abu Dhabi. We don’t know what to expect from that new layout either.”