Russell fastest from Leclerc in Singapore practice
Mercedes driver George Russell led Ferrari's Charles Leclerc in practice at the Singapore Grand Prix.
A late lap from Leclerc, who was 0.198 seconds off Russell's pace, split up what had been an all-British top three.
McLaren's Lando Norris was third fastest, 0.273secs behind Russell, and Ferrari's Lewis Hamilton fourth, 0.499secs off the pace.
The top five, concluded by McLaren's Oscar Piastri, were all on the soft-compound tyres, while Red Bull's Max Verstappen was the fastest driver using medium tyres in sixth place.
The four-time champion was 0.732secs off the pace and 0.519secs quicker than Mercedes' Kimi Antonelli behind him in seventh, also on the medium tyres.
It was the only practice session of the weekend with sprint qualifying taking place at 13:30 BST.
The split between tyre compounds made it hard to form any conclusions about relative pace.
Russell will start Sunday's race from the back as a result of a penalty for using too many engine parts, following his engine failure while running third in the closing stages of the Bahrain Grand Prix in Malaysia.
He and Antonelli are also running different specifications of car, Russell reverting to a previous spec and the Italian the new aerodynamic package introduced in Malaysia.
This is so Mercedes can get a better read of whether the upgrade package is working after struggling for pace in Malaysia when they expected to make a step forward.
Verstappen took his and Red Bull's first win of the year at Sepang, and looked quick at times in the session before tyre strategies diverged.
His team-mate Isack Hadjar, also on the medium, was eighth fastest, with Alpine's Pierre Gasly and Racing Bulls' Liam Lawson completing the top 10.
Aston Martin's Fernando Alonso was in the top 10 for a time, but dropped back in the closing stages of the session to end up 14th.
The racing action is taking place amid air-quality warnings in Singapore as a result of haze from wildfires in Indonesia, primarily caused by illegal slash-and-burn practices used by farmers and companies as a cheap method to clear vegetation.
This is leading to record levels of air pollution in the city state and citizens are advised to limit outdoor activities.
Singapore Grand Prix
9-11 October
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