By Rory Carroll

LAS VEGAS (Reuters) - Last year's winner George Russell of Mercedes topped the timesheets in the final free practice for the Las Vegas Formula One Grand Prix on Friday, edging Red Bull's Max Verstappen and the Williams of Alexander Albon.

Qualifying for Saturday night's race on the Las Vegas Strip is set to take place later in the evening, with rain threatening.

Russell posted a fastest time of one minute, 34.054, which was 0.227 seconds ahead of four-times world champion Verstappen, with Albon 0.821 seconds behind the Mercedes.

McLaren's championship leader, Lando Norris, struggled with an electrical issue with his car that limited his session.

The Briton, who has a 24-point lead over teammate Oscar Piastri, was the fastest in Thursday night's second practice, which was twice red-flagged due to a suspected loose drain cover.

Piastri lost telemetry in his car, which also curtailed his practice. He finished 19th and Norris 20th.

McLaren have already wrapped up their second consecutive constructors' title this year and are fighting to secure their first drivers' title since 2008.

They did not perform well in Las Vegas last year and the team have downplayed expectations heading into the race, which is the 22nd of the 24-race calendar.

(Reporting by Rory Carroll in Las Vegas; Editing by Peter Rutherford)