Oscar Piastri stamps authority in Belgian GP practice as Carlos Sainz suffers 'critical problem'

Oscar Piastri set the pace in the sole practice session for this weekend's the Belgian Grand Prix and ahead of sprint qualifying.

As the chequered flag fell at the Spa-Francorchamps circuit, Piastri set the fastest lap of the session with a 1:42.022s, finishing a comfortable 0.404s ahead of Red Bull's Max Verstappen, who had followed the F1 championship leader over the line.

As for Piastri's closest title challenger in Lando Norris, his team-mate struggled once the field switched to the soft tyres, finishing half-a-second adrift of the Australian.

That will be of concern to Norris, particularly with the McLaren duo sporting a new power unit in their MCL39s, the fourth and final one of the season they are allowed.

More Carlos Sainz misery

Carlos Sainz, meanwhile, who has often bemoaned his lack of clean weekends that have undermined his maiden campaign with Williams, the Spanish driver could not have started the latest outing in worse fashion.

Sainz had no sooner made his way down the pit lane than he radioed in that he had a problem with the car and was in 'limp home' mode. He was informed it was "a critical problem" and to avoid load on his return to the garage, forcing him to trudge his way back slowly.

With a fuel system issue diagnosed, Sainz had to wait until just after the half-hour mark to return to the track, finishing 11th quickest at the end.

For this weekend, Pirelli has made a change it has not undertaken for three and a half years since the 2022 Australian Grand Prix, with a step in its compounds, opting for the C1 hard, and then C3 and C4 as medium and soft, believing it will force a two-stop strategy.

The hard was used by the majority of the drivers from the start, although Verstappen, with a new front wing on his RB21, and team-mate Yuki Tsunoda opted for the medium compound for their first forays.

Following early sighter laps across the board, it was Verstappen who naturally held sway early on in running a softer tyre two steps lower than the hard runners, initially with a 1:45.545s before following up with a second push lap of 1:44.236s.

After 25 minutes, and on the hard tyres, Leclerc took over at the top with a 1:44.148s, edging out Verstappen by 0.088s. Piastri moved to within five thousandths of a second of Leclerc on hard tyres, following which a period of long running followed.

Alpine's Franco Colapinto was the first to take to the softs soon after, and whilst obviously setting personal bests in all three sectors, the Argentinian driver's lap was only good enough to elevate him from 19th to 16th at the time, 1.579s adrift.

Moments later, Colapinto appeared to clearly impede Mercedes' George Russell. Although initially noted by race control, it was not felt necessary to investigate.

A later push lap from Colapinto elevated him to eighth. With 12 minutes to run, he remained the only driver to have used the soft rubber until Lance Stroll took to the circuit with the red-striped Pirellis in his Aston Martin.

The Canadian driver flew to the top of the timesheet by 1.036s over Ferrari's Charles Leclerc.

Piastri followed suit on softs soon after, and it was no surprise to see the Australian take 0.989s out of Stroll's time.

On his run, Verstappen was faster than Piastri in the first and third sectors but 1.1s slower in the middle, leaving him 0.530s adrift.

Russell and team-mate Kimi Antonelli shunned the softs in favour of the mediums, with the duo slotting into second and fifth in the standings before late soft-tyre fliers from their rivals.

Norris, meanwhile, compromised his soft-tyre outing with a run onto the gravel out of Stavelot that compromised him for the remainder of the lap.

On their second push laps on the softs, Piastri improved to his pace-setting 1:42.022s, followed by Verstappen and Norris, with Russell and Antonelli an impressive fourth and sixth, either side of Leclerc.

Lewis Hamilton was seventh, 1.063s off the pace despite a new rear suspension on his Ferrari, with Stroll eighth, then team-mate Fernando Alonso. Racing Bull's Isack Hadjar completed the top 10.