Austin (United States), Nov 3 (IANS): Mercedes driver Nico Rosberg believes that an Energy Recovery System (ERS) error was the main cause for his defeat at the hands of teammate Lewis Hamilton in the Formula 1 United States Grand Prix.

"I made a mistake because I used the wrong thing to get more ERS. When I saw him coming I decided to go for extra boost, but I never got it," Rosberg was quoted as saying by Xinhua.

"I thought I was using the right thing but there was a delay in that one. If I did it with a button, it would be immediate but with a switch there is a delay, so I never got the extra ERS," said the German, who started from pole but surrendered the lead to race winner Hamilton.

Rosberg added, "I had a big drop off, which is why in the last metres he got a good jump on me. So that was a mistake that I didn't know about."

The result further widened the gap in the drivers' standings between the second-placed Rosberg and leader Hamilton, who now has a 24-point advantage heading into next weekend's Brazilian Grand Prix.