Mercedes still wary of reliability stopping Hamilton winning fifth title

Mercedes team principal Toto Wolff says Mercedes is still aware that reliability could stop Lewis Hamilton from taking his fifth world drivers championship despite him holding a 67 point advantage over title rival Sebastian Vettel with just four races remaining.

Mercedes has enjoyed a huge upturn in form since the summer break, with Hamilton taking 168 out of a possible 175 points since Silverstone, form that has left his title rival Vettel licking his wounds and Ferrari looking foolish once more.

Despite their charge towards a fifth straight constructors championship also, Wolff says he hasn't taken his eye off the ball and neither has the team, admitting that reliability could still play its part.

"Freak incidents happen everywhere," he said. "A DNF and the consequent bad result suddenly wipes off a large chunk of your points. I know from the public standpoint it doesn't look likely, but this is motor racing, it's a sport, anything could happen.

"I don't want to even think about him breaking a finger. Anything can happen in motor racing.

"I don't want to dwell too much about it, because this is bad karma too, so let's just get it done, let's go to Austin, let's have a strong race weekend and then hopefully see the championship."

Rumours suggest that Ferrari's recent loss of performance could be down to them playing the long game with reliability also, turning down engines to save mileage and wear in order to finish the season with just three elements like the rules permit.

The Mercedes boss however isn't looking at what their rivals are doing in terms of power unit strategy, instead focusing on bringing home another world championship for Mercedes and Hamilton.

"Somehow none of us are looking at where Ferrari is or how the championship goes; it's just aligning those weekends that eventually hopefully will lead to a situation where we say we have won it."