Lewis Hamilton revealed he was fearing another retirement en route to a landmark victory for the Formula One world champion in the United States Grand Prix on Sunday.

The Mercedes driver was leading with 15 laps remaining in Malaysia this month, but failed to finish after his car dramatically caught fire.

Hamilton had no such trouble at the Circuit of The Americas, claiming his 50th F1 victory after starting on pole to reduce team-mate Nico Rosberg's lead to 26 points with three races remaining.

The Brit said he felt far more at ease in Texas, but was still fearful of another engine failure.

He said: "I just focus on doing the best job I can. Honestly, beyond doing the job... I felt comfortable doing the job.

"I was just the whole race concerned the car was not going to make it so right, I've been told the line.

"I was just in fear of the same thing, the same feeling, the sound that I heard in Malaysia, so I was grateful that the car made it across the line and I have a lot more confidence in his reliability.

"It’s going well for him [Rosberg]. I've just got to continue to do my job and hope for the best."

Hamilton will attempt to put more pressure on Rosberg in the Mexico Grand Prix next weekend.