MANAMA - Red Bull's Sergio Perez set the pace in the first practice session of the Formula One season in Bahrain on Friday with Aston Martin's Fernando Alonso denying the champions a one-two on the timesheets.

Perez lapped the Sakhir circuit with a best time of one minute 32.758 seconds on soft tyres, 0.438 quicker than Spaniard Alonso, with reigning champion Max Verstappen third and a further two tenths slower.

Double world champion Alonso, the oldest man on the grid at 41, will be starting his 20th season after moving from Renault-owned Alpine.

McLaren's Lando Norris was fourth, ahead of Ferrari's Charles Leclerc and Aston Martin's Lance Stroll -- the Canadian racing after breaking both his wrists in a cycling accident last month.

Stroll was kept waiting for the first 20 minutes due to an ignition problem.

Once-dominant Mercedes had a quiet session on a hot afternoon with seven times world champion Lewis Hamilton 10th and team mate George Russell 11th on medium tyres.

McLaren's Oscar Piastri was the highest-placed rookie in 12th, with AlphaTauri's Nyck de Vries 16th and Williams' Logan Sargeant 18th.

Ferrari's Carlos Sainz was last after a big spin.

Red Bull are favourites for the weekend in Bahrain after setting the pace in testing.

(Reporting by Alan Baldwin, editing by Ken Ferris)