Russell won last year's race in Singapore from pole but the Briton is set to start at the back of the grid on Sunday due to a power unit penalty following an engine failure five laps from the finish in Malaysia.
With the Marina Bay Street Circuit hosting a sprint this year, drivers had just one practice session available - albeit in the daylight - to get to grips with the track ahead of sprint qualifying under the lights later on Friday.
Russell clocked one minute and 32.274 seconds at the dusty circuit on the streets of Singapore, nearly two-tenths of a second faster than Ferrari's Charles Leclerc while reigning champion Lando Norris was third-fastest.
Championship leader Kimi Antonelli, who leads Russell by 84 points, was only seventh-fastest behind Ferrari's Lewis Hamilton, McLaren's Oscar Piastri and Red Bull's Max Verstappen - the fastest driver on medium tyres.
Verstappen had initially set the fastest time earlier in the session but he was called back into the pit garage, with team principal Laurent Mekies explaining his radio was not working.
"That made everyone's lives difficult. We had nothing at all and it is quite difficult to run these cars with no radio," Mekies said.
Verstappen's team mate Isack Hadjar, Alpine's Pierre Gasly and Racing Bulls' Liam Lawson completed the top 10.