SHANGHAI - Aston Martin's Lance Stroll lapped fastest in Friday's sole free practice session for the Formula One Chinese Grand Prix followed by McLaren's Oscar Piastri, as teams sought to get to grips with a circuit they have not visited in five years.

How the current ground-effect era cars would respond to the track, and whether an unexpected surface treatment that caught drivers by surprise on Thursday would prove too tough on tyres, was the talk of the paddock leading into the session.