Lewis Hamilton's bid to tie up a sixth Formula One world title will have to be completed in Mexico City without the aid of race engineer Peter Bonnington.

Hamilton must outscore Mercedes team-mate Valtteri Bottas by at least 14 points in Mexico to secure a third successive title with three rounds of the season to spare.

However, he is without regular engineer Bonnington, who will miss the Mexico and United States races as he undergoes a medical procedure, according to the official Formula One website.

Performance engineer Marcus Dudley is replacing Bonnington for the weekend's Grand Prix at the Autodromo Hermanos Rodriguez.

Lewis ends #FP1 top of the pile in Mexico City. He clocks a 1:17.327. VB is P5 with a 1.18.005  #MexicoGP pic.twitter.com/tgudvhhZTW

— Mercedes-AMG F1 (@MercedesAMGF1) October 25, 2019