Mercedes driver Nico Rosberg feels that he should have won the Russian Grand Prix after having a positive weekend ruined by a throttle issue.
The German qualified on pole and led early on but had to retire after his throttle pedal broke while driving behind the safety car.
The 30-year-old admitted that it was disappointing and that he felt confident that he could win the race to close the gap on the championship leader Lewis Hamilton.
The former Williams man told the BBC: "It has made the championship more difficult but I am never going to win the championship this year anyway if it continues like that, breaking such normal things on a day when I should have won the race.
"It is very disappointing but of course, I will come back like I always do, there is no problem and I will keep pushing and keep attacking and trying in Texas."
Rosberg is in second place in the Drivers' Championship but Hamilton needs just two points at the US Grand Prix to seal his third world title.