Charles Leclerc and Carlos Sainz have ended a marathon opening day at the Las Vegas Grand Prix fastest for Ferrari.

It was a stunning performance for the Sainz said of the Ferrari garage after completing a chassis swap following Free Practice 1.

That was necessitated when a loose water valve cover inflicted heavy damage on the Spaniard’s car and forced the abandonment of opening practice – and the delay of Free Practice 2.

Sadly, he’ll cop a grid penalty for a new energy store, the team’s argument of force majeure accepted by officials who were nonetheless forced under the regulations to penalise the Scuderia.

Leclerc ended proceedings fastest by 0.5s, Sainz 0.01s up on Fernando Alonso in third and Max Verstappen only sixth fastest for Red Bull – two places back from team-mate Sergio Perez.

The session finally got underway 2.5 hours after its originally scheduled time, and 30 minutes after the FIA had hoped.

That delay was caused by repairs being made to the track after a valve cover broke free just eight minutes into opening practice.

The fix was to pull them out and tar them over, a process that necessitated an extended delay – so much so that fans were sent home before cars headed out for Free Practice 2.

When cars were finally released, Lando Norris and Oscar Piastri headed the train out, the Australian recording the first timed lap at 1:43.832s.

Norris, meanwhile, was forced back into the lane as his car went into limp home mode.

It was busy on track, with all 20 drivers banking laps on a mixture of soft and medium rubber.

At the wheel of a freshly built replacement Ferrari chassis, given his original one was damaged beyond repair in Free Practice 1, Sainz went fastest with a 1:39.891s.

He was shadowed on the timing screens by team-mate Leclerc, who was 0.116s slower.

Inside the McLaren garage, the bodywork was coming off Norris’ car as the team worked to understand the bug that curtailed his opening run.

Turn 12, the left-hander onto the Strip was proving troublesome with both Perez and Kevin Magnussen running off.

Lance Stroll had a moment at the other end of the Strip, running deep at Turn 14 to briefly draw the yellow flags.

After 15 minutes, the ultimate pace had only dropped to 1:38.209s, recorded by Verstappen on a set of medium tyres.

The track was continuing to evolve, which saw times gradually improve and drivers begin pushing the limits.

Verstappen had a brief off at Turn 12 as he out-braked himself and took to the escape road.

Just after the hour mark, Leclerc lowered the benchmark to 1:36.660s, with Sainz second by 0.082s, both on the soft tyre.

When Verstappen completed his single lap run, he was only fastest enough for third, a 1:36.960s.

Pit entry was proving tricky, a number of drivers picking up bad sportsmanship flags for crossing it.

The line was painted in an unusual purple rather than white or yellow as is typical, with drivers approaching at some 300km/h.

It also required them to peel off the racing line early, moving well inside of the apex of the ultra-fast final corner.

With 40 minutes remaining, Alonso shot to the top of the timesheets, 0.003s quicker than Leclerc who in turn was 0.003s faster than Lewis Hamilton.

Indeed, the top five were split by just 0.085s, with the fastest Red Bull in seventh, 0.3s off the pace.

That preceded another flurry of qualifying simulation laps, Verstappen improving to 1:36.307s to sit 0.047s clear of Sainz.

Leclerc had also bolted on another set of soft tyres, going 0.5s faster than his Dutch rival to the second split.

He completed the lap with a 1:35.696s, leaving him 0.611s clear of the pack.

Sainz improved to 1:35.821s in the other Ferrari to leave the Scuderia first and second, with Perez slotting in third ahead of Verstappen in fourth.

That became sixth for the champion-elect as Alonso and Valtteri Bottas went faster on their qualifying runs.

With high fuel, race simulations following for the remainder of the extended, 90-minute session, Leclerc ended up fastest from Sainz.

A final hour of practice remains and will likely offer a more accurate reflection of the true pecking order as teams refine and converge on downforce levels.

While Ferrari has shown promising pace, Aston Martin and Williams also had encouraging days.

Alfa Romeo Sauber showed well with Valtteri Bottas while Nico Hulkenberg showed well in the older-spec Haas while his team-mate was some 0.4s slower.