Carlos Sainz led Charles Leclerc in a Ferrari one-two in an apparently unrepresentative second practice session at the Singapore Grand Prix.
Sainz was 0.208 seconds quicker than his team-mate but both Leclerc and Max Verstappen’s Red Bull had sessions disrupted by technical issues.
Verstappen did only seven laps and ended up fourth, splitting the Mercedes of George Russell and Lewis Hamilton.
Esteban Ocon’s Alpine was fifth fastest ahead of Alfa Romeo’s Valtteri Bottas.
Leclerc and Verstappen had delayed starts to the session as their teams made changes to their cars.
Ferrari were changing parts and managed to get Leclerc out for the final half of the session, but it meant he could do only two runs and no race-simulation laps.
Red Bull – at the centre of a controversy over allegations they breached Formula 1’s budget cap last year – have not provided an explanation as to the delays in Verstappen’s session.
Not only did he not get out until about half an hour in, but he then did only one flying lap before spending another long period in the pits, emerging only for two more relevant laps.
Hamilton was quickest in the morning session from just ahead of Verstappen but appeared to struggle to put a representative lap together on the fastest ‘soft’ tyres in the second session.
Behind Ocon and Bottas, Alpine’s Fernando Alonso, Red Bull’s Sergio Perez and Aston Martin’s Lance Stroll completed the top 10.
Alex Albon, returning to F1 after missing the Italian Grand Prix because of a medical emergency, completed the session which he had said would be the biggest test of his fitness.