Bahrain Grand Prix: Lewis Hamilton struggles in first practice

Alpha Tauri's Pierre Gasly set the pace in first practice at the season-opening Bahrain Grand Prix as the true competitive picture remained unclear.

Gasly was 0.364 seconds quicker than Charles Leclerc in second place, but using the soft tyres while the Ferrari was on the slower medium.

The second Ferrari of Carlos Sainz was third, ahead of Mercedes' George Russell and Red Bull's Max Verstappen.

Mercedes' Lewis Hamilton was seventh, behind Aston Martin's Lance Stroll.

The Mercedes drivers insisted again before the session started that their car is not yet absolutely competitive as the team battle to get on top of aerodynamic problems causing it to bounce on the straights.

And the Mercedes did not look comfortable to drive out on the Sakhir track, the drivers battling a lack of rear grip.

Russell and Hamilton were also on the soft tyre when he set his time, while Verstappen was on the medium.

Leclerc's fastest time came despite the 24-year-old spinning at high speed at Turn 11 on his first attempt. The error damaged his tyres, but he still managed to improve on his next lap.

Alpine's Fernando Alonso was eighth quickest, while his team-met Esteban Ocon had to switch to an earlier design of sidepod after an upgraded version introduced for this weekend exploded on the straight early in the session.

Ocon ended the session 12th, split from Alonso by Alpha Tauri's Yuki Tsunoda, Red Bull's Sergio Perez and Chinese rookie Zhou Guanyu.

A clearer picture of where the teams lie in comparison to each other will come in the second session, which starts at 18:00 local time (15:00 GMT), when teams will run qualifying and race simulation tests.