Max Verstappen laid down an early marker on the opening day of pre-season Formula One testing in Bahrain on Lewis Hamilton suffered a nightmare start as a sandstorm swept across the Sakhir track. Verstappen, long regarded as heir apparent to seven-time world champion Hamilton, clocked a best time of 1min 30.674sec in the Red Bull as he piled up an eye-watering 139 laps. "We had a very positive day and managed a lot of laps even though the track conditions were quite difficult," said Verstappen, who was third in the championship last year. "We don't need to talk about pace yet and it isn't really a discussion until we get to Q3 at the first race weekend - it's only then you see the real pace in all the cars." In stark contrast, Hamilton was only 10th fastest in 1:32.912 although his 42 laps dwarfed the six managed by Mercedes teammate Valtteri Bottas, the slowest man on the track in 1:36.850. Bottas, runner-up to Hamilton in the 2020 championship, even finished behind Haas rookies Nikita Mazepin and Mick Schumacher. "It was not a good start," admitted Mercedes team boss Toto Wolff. "We had a gearbox problem that came out of nowhere which we haven't been able to identify yet." However, Wolff didn't appear too concerned over his team's struggles with two more days of testing to go. With just three days testing in total compared to six and eight in Barcelona in recent years, Wolff said the brief Gulf visit offers only a "vague picture" of each team's readiness for the new season, which starts in Bahrain on March 28. Hamilton shrugged off what proved to be a frustrating day. "I've never seen a sandstorm come through here before in all the years that I've driven at this circuit," said the 36-year-old Briton. "The sand was moving like rain would move. Having sand on the tyres isn't good for their longevity and getting consistency on long runs is difficult." He added: "We only have a day and a half in the car before the first race. I'd like to think my nine years' experience with this team will help me get the best out of it."