The Mercedes duo headed Lando Norris and Charles Leclerc in a busy session highlighted by a dusty circuit, locked brakes, and cars sliding off the road.

A key takeaway from 2023’s event had been the lack of grip offered up by the track surface.

Uniquely, the circuit is opened to traffic during the day, which sees oil and detritus deposited on the track.

It was dusty too as Free Practice 1 began with drivers struggling for traction such that Liam Lawson, on his first lap out of the pits, likened it to driving in the wet.

Conditions were cool, air temperatures of 14 degrees with the track dropping quickly, not helping drivers get their tyres into the ideal operating window.

Few were taking risk as a result, staying well clear of the walls under braking as they struggled for grip.

The track did evolve rapidly but it remained a long way even from last year’s track times.

Most opted for medium tyres, though Red Bull Racing sent both Max Verstappen and Sergio Perez out on softs after the opening 15 minutes.

Aston Martin’s session was interrupted on both sides of the garage; a brake duct issue for Fernando Alonso but more serious attention was paid to Lance Stroll’s car.

His car was on stands, with attention being paid to the rear end.

After 20 minutes, the racing line had largely cleaned up, and there was a degree of lateral traction, but it remained extremely dusty off line.

Midway through the session, Hamilton topped proceedings with a 1:36.927s.

It was a lap more than four seconds faster than those that had started the session, highlighting the improving conditions.

Times had also moved significantly faster that the same session a year ago.

For a time, it was a Mercedes one-two at the top of the timesheets until Charles Leclerc went second, 0.085s slower than Hamilton, with 20 minutes remaining.

Soon after he went fastest with a 1:36.430s, which became second best when Carlos Sainz went 0.2s faster, their times set on the soft compound tyres.

Ferrari has a notable upgrade package, with front wing and a new floor, which it is running in practice this weekend, fitted only to Sainz’s car during opening practice.

No decision has yet been made on whether it will remain on the cars for qualifying and the race.

The Scuderia headed into the weekend favourites, based on performances in the United States and Mexico recently, and its form in Vegas a year ago.

Norris soon bested the Ferrari pair, with Oscar Piastri fourth fastest approaching the final 10 minutes, the top of the timesheets inline with expectations.

It didn’t stay that way as teams timed their programs differently, with track evolution a continued factor.

Mercedes making the most of that by sending Russell and Hamilton out late on a set of soft tyres, Russell fastest inside the final five minutes with a 1:35.619s, his team-mate going 0.132s faster.

Those who’d delayed the soft tyre runs reaped the rewards of the improved track conditions, leaving the final order somewhat misrepresentative.

In truth, Mercedes was rapid throughout the session though Ferrari offered suggestions that it has performance in hand.

McLaren too was in the mix, while Red Bull Racing looked the weakest of the top four teams.

RB struggled throughout, with Yuki Tsunoda and Liam Lawson at the bottom of the timesheets with suggestions of tyre graining in the cool conditions.

A second hour of practice is to follow today, starting at 22:00 local time (17:00 AEDT Friday).