AUSTIN, Texas -Ferrari drivers Carlos Sainz and Charles Leclerc each led a free practice session on Friday ahead of a U.S. Grand Prix that could seal Red Bull's first Formula One championship double since 2013.Sainz was quickest in the first hour at Austin's Circuit of the Americas while Leclerc topped the timesheets in the extended 90-minute second stint that was mainly devoted to testing Pirelli's 2023 prototype tyres.Red Bull's Max Verstappen, who wrapped up his second drivers' championship in Japan on Oct.
9, was second in practice one, 0.224 off the pace, with seven times world champion Lewis Hamilton third for Mercedes.Sainz's best lap was a one minute 36.857 seconds while Leclerc, who sat out the opening session while young Israeli development driver Robert Shwartzman made his race weekend debut, set a 1:36.810 in the afternoon.The Monegasque did his best lap on this year's tyres, however, as one of a handful of drivers allowed to do half an hour of regular running to make up for missed time.Alfa Romeo's Valtteri Bottas and McLaren's Daniel Ricciardo were second and third in that less representative second session with Sainz fourth.Verstappen won last year in Texas and another victory with fastest lap on Sunday would secure Red Bull the constructors' crown with three races to spare.It would also equal the record for most wins by a driver in a single season, lifting Verstappen alongside Michael Schumacher and Sebastian Vettel on 13.The champion was not entirely happy in the opening session, however, complaining that "there must be something wrong with the car because there is no front end in low speed".