No 'Bono' for Hamilton in Mexico, Austin

Mexico City - Lewis Hamilton will bid to claim his sixth drivers' world title without his regular Mercedes race engineer Peter 'Bono' Bonnington.

Bonnington is absent from the championship showdown in Mexico this weekend and the United States one week later, having stayed in Britain to undergo a medical procedure.

Hamilton is seeking to outscore Mercedes team-mate Valtteri Bottas, initially by 14 points in Mexico, to seal the title.

Bonnington is expected to return for the Brazilian Grand Prix in mid-November.

He will be replaced, as the voice in Hamilton's ear during each session and race, by performance engineer Marcus Dudley. He, in turn, will be replaced by Dom Riefstahl, a member of Mercedes' race support team.

Bonnington has been Hamilton's race engineer in all four of his triumphant championship-winning seasons with Mercedes.

The pair have worked together since 2013 and their frequent radio exchanges have been a feature of Formula One in recent years.