McLaren's Lewis Hamilton set the pace during Friday's first practice session for the Bahrain Grand Prix.

The reigning world champion has endured a difficult start to the new season with his McLaren car off the pace.

However, he made a promising start to the fourth race weekend of the season after clocking a fastest lap of one minute 33.647 seconds in hot conditions around the Sakhir circuit.

The BMW Sauber pair of Nick Heidfeld and Robert Kubica were second and third respectively, while championship leader Jenson Button was fifth for Brawn GP.