Mercedes motorsport boss Toto Wolff has described Lewis Hamilton and Nico Rosberg as "almost like enemies" in their battle for this year's Formula One world title.

With six races left, starting with Sunday's Singapore Grand Prix, just 22 points separate the pair as they fight it out for the sport's most-prized trophy.

Reflecting on what has unfolded between them on-track this season, Wolff concedes there has been a noticeable deterioration in their roles as team-mates.

Wolff said: "It has changed from an almost amicable relationship at the beginning of the season to a very intense moment, where it was almost like realising these two are enemies competing for the title.

"These boys have been calibrated their whole life that their main priority is to win the F1 drivers' championship.

"And here they go - they are in the same car, competing against each other for that trophy, and one is going to win and one is going to fail. This is a new experience for them - a difficult experience maybe."

Speaking of the two drivers, Wolff admitted Rosberg had a ruthless side, adding: "Nico has always been like this. I don't know why anyone had the perception of him being Mr Nice Guy.

"Lewis has found his own way and developed extremely impressively. He doesn't need so much management. It makes no sense to try to change a personality. It is his personality and it makes him function well."