MEXICO CITY: Kimi Antonelli admitted he felt tense and below his best on Saturday after qualifying fifth for Sunday's Mexico City Grand Prix, where he can become Formula One's youngest world champion.

The 20-year-old Italian, who missed Thursday's media day at the Autodromo Hermanos Rodriguez with a virus, will start from fourth as Red Bull's four-time world champion Max Verstappen has a grid penalty.

He needs to finish ninth or better to make certain of his first drivers' title and Italy's first since Alberto Ascari for Ferrari in 1953, even if one of his main rivals – Mercedes team-mate George Russell or Ferrari's seven-time champion Lewis Hamilton wins.

Hamilton will start Sunday's race from his record 105th pole position, and first for Ferrari, with Russell second on the grid.