Nico Rosberg has expressed his displeasure with title-winning team-mate Lewis Hamilton making contact with him at the start of the United States Grand Prix, labelling it as 'extremely aggressive'.

On the day that saw Rosberg throw away any hope of keeping his already slim title hopes alive by running off whilst leading with eight laps remaining, the German would be forced to watch as Hamilton came by to seal back-to-back titles for Mercedes.

However, it was contact with Hamilton at the first corner that would leave Rosberg fuming, the Briton coming up the inside and sliding wide in the slippery conditions, forcing the German off the track and down to fourth place.

Branding the move as 'extremely aggressive', tensions appeared to rise further in the cool down room before the podium when Hamilton threw a cap Rosberg's way, who responded by throwing it back. Indeed, though Rosberg would fight back in the race, he was disappointed to come off worse in another tete-a-tete

"At turn one for sure it was very aggressive but I don't what to say yet because I haven't seen it yet so I can't comment," he said speaking directly after the race. "As always it was extremely aggressive, we hit each other, or I would say Lewis came into me, so that is not good but I can't say more than that."

Despite showing impressive pace at times in the race, Rosberg's efforts were undone by him running wide at turn 17, an error he was mystified by.

"I just got lots of wheel spin - the slip has never happened to me ever, not even in testing, racing or anything like that. I don't know how to explain it. It is unbelievable. That was really, really tough at the time to lose the lead like that and to lose the win."