The defending double world champion, who had struggled with his car in the opening session to finish sixth, was quickest in a best lap of one minute 12.462 seconds, 0.065 clear of the Monegasque local hero who is bidding for his third successive 'home' pole position.

Carlos Sainz, who was quickest in the first session, was third in the second Ferrari ahead of Aston Martin's two-time champion Fernando Alonso, Lando Norris of McLaren and seven-time champion Lewis Hamilton of Mercedes.

Last year’s winner Sergio Perez was seventh in the second Red Bull ahead of a resurgent Valtteri Bottas of Alfa Romeo and the two Alpines of French duo Pierre Gasly and Esteban Ocon.

The session was run in near-perfect conditions, a warm afternoon sun touching 27 degrees as it shone from a wide blue sky over the Mediterranean principality. The track temperature was 45 degrees.

After an encouraging morning run behind the pace-setting Ferrari of Sainz, Hamilton quickly confirmed that Mercedes’ upgrade package was working well as he topped the times on mediums in 1:15.735.

He was soon outpaced by team-mate George Russell in 1:15.482 before, in a flurry of pace, Alonso, Verstappen and Hamilton took top spot.

Verstappen improved again in 1:13.857 to set the pace while the two Ferraris narrowly avoided a collision in the ‘Swimming Pool complex’ before the Dutchman trimmed his time down to 1:13.312.

After 24 minutes, Alonso swapped his mediums for a set of softs and the serious stuff began with him blasting to a best time of 1:12.786, an improvement of nine-tenths on his previous fastest lap.

Fellow-Spaniard Sainz also switched to softs and delivered a lap in 1:12.569 to go top again as Alonso amused himself with a joke on team radio.

"I’m speechless with these guys complaining about the traffic," he said, as his rivals struggled to find space on a crowded track.

With 20 minutes remaining, Verstappen and Leclerc, who had fine-tuned their cars after first practice, surged clear of the field, the Red Bull fastest in 1:12.462, shortly before Sainz crashed as he came out of the Swimming Pool complex.

The session was red-flagged as Sainz climbed out of his Ferrari, having hit the unforgiving barriers with his right front section. "All good," he said, confirming he was unhurt.

On resumption, Alex Albon, who had crashed in the first session, re-joined the fray in his repaired Williams as the shadows began to stretch across the circuit.

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