San Francisco Frontiers - Antonelli romps opening practice ahead of Russell

The 19-year-old, chasing a fourth consecutive victory to extend his 20 points lead ahead of Russell in the title race, was fastest on both hard and soft tyres as he wound up on top in one minute and 13.402 seconds.

This lap took him 0.142 seconds clear of pre-season favourite Russell in a session interrupted by three red flags.

Behind them were the two Ferraris with Lewis Hamilton in third ahead of Charles Leclerc, and four-time champion Max Verstappen down in fifth for Red Bull.

World champion Lando Norris was sixth ahead of his McLaren team-mate Oscar Piastri, rookie Arvid Lindblad of Racing Bulls, Nico Hulkenberg of Audi and a revived two-time champion Fernando Alonso of Aston Martin.

The three red flags came after Liam Lawson stopped his Racing Bulls car on track with gearbox problems, Alex Albon hit a marmot in his Williams and crashed and finally Esteban Ocon smacked the walls in his Haas.

After much paddock gossip about his future, Verstappen was soon on top once the sole session began in earnest, lapping the track in 1:17.432 before Piastri went faster and the Dutchman responded in 1.15.895.

Verstappen had suggested on Thursday that he was likely to remain in F1 if a mooted switch next year to a 60-40 split between mechanical and battery power was introduced, to replace the 50-50 in use in this first season of the new ‘hybrid era’.

Most teams introduced update packages with Mercedes bringing a major set of new parts and McLaren their second. Ferrari and Aston Martin appeared to have no updates.

The session was stopped by a red flag after Liam Lawson came to a halt with gearbox problems after 15 minutes, prompting a delay as his Racing Bulls car was cleared. The action resumed after five minutes.

For Lawson, this was another unlucky setback following his problems in Miami, earlier in May, when a technical failure caused him to collide with Alpine’s Pierre Gasly and half-flip his car.

As they settled, Piastri and then Russell topped the times on a bright sunlit morning at the Circuit Gilles Villeneuve, the Australian responding to clock 1:14.963 and go nearly half a second clear of the Briton with Antonelli third, before Hamilton leapt to second.

Albon then lost control of his Williams at Turn Seven after 28 minutes, suffering damage to the rear wing and rear wheels after smacking the barriers as he sought in vain to avoid hitting a marmot (a large ground squirrel native to north America, also known as a groundhog).

- Mercedes revelling -

After a 15-minute break, with the time lost added to the session, the action resumed and Russell promptly trimmed his time to within 0.013 seconds of Piastri’s before Antonelli stole top spot only to see Russell take control in 1:14.560.

Both trimmed their times, Antonelli running quickest in 1:14.392 by 0.052 with 23 minutes remaining – and Piastri third adrift by more than half a second.

It was clear that the Mercedes upgrade was working and the drivers were revelling in a.high-speed rivalry.

With 15 minutes to go, Hamilton rose to third, 0.36 off the pace, while Russell switched to softs to clock 1:13.850 and go top, followed by Antonelli who did 1:13.402 to regain the initiative.

L.Lopez--SFF