Lewis Hamilton's replacement driver set the fastest time Friday in the first practice session for the Sakhir Grand Prix.
George Russell, given his chance with Mercedes after Hamilton tested positive for COVID-19, completed a lap of the desert track under floodlights in 54.546 seconds. His time was 0.176 seconds faster than Red Bull driver Max Verstappen and 0.265 ahead of Alexander Albon.
Hamilton, who has already clinched the season-long championship, is self-isolating for 10 days and could also miss the year’s final race in Abu Dhabi next weekend.
The 22-year-old Russell has bigger feet than Hamilton and had to squeeze into Size 10 racing boots rather than his usual Size 11.
Mercedes driver Valtteri Bottas, who is fighting to hold off Verstappen for second in the championship, was fourth quickest, 0.322 behind Russell.
Bottas trails Hamilton by 131 points and leads Verstappen by 12 — although Verstappen has a slower car.
Drivers are again racing at the Bahrain International Circuit in Sakhir, but on a smaller high-speed outer track.