Title favorite Lando Norris was the fastest for Formula One champion McLaren after a power outage disrupted the first day of preseason testing in Bahrain on Wednesday.

The session was extended by an hour into the evening after the outage, caused by a substation failure, plunged garages into darkness with engineers using torches as mechanics connected backup generators.

"I came to the pits and said 'it's dark out here. I need to change my visor'. Then I realized there are no floodlights around," Mercedes' George Russell told Sky Sports.