The Monaco Grand Prix is live on 5 Live and the BBC Sport websiteFerrari's Charles Leclerc headed Red Bull's Sergio Perez in a close first practice at the Monaco Grand Prix.
Leclerc, who lost the championship lead to Red Bull's Max Verstappen in Spain, was 0.039 seconds ahead.
Ferrari's Carlos Sainz was third, 0.07secs behind Leclerc, with Verstappen fourth after damaging his tyres on his final run with a lock-up.
McLaren's Lando Norris was fifth, Mercedes' George Russell and Lewis Hamilton eighth and 10th.
There were no crashes, but a number of drivers ran off track at the first corner. Along with Verstappen, Leclerc, Perez and Haas driver Kevin Magnussen all had moments there.
Verstappen had gone quickest with his first run on then medium tyres, having started the session on the hards, but after he braked too late into Sainte Devote on his next flying lap his session was over and the Ferrari drivers and Perez managed to leapfrog the world champion.
Williams driver Alex Albon had a very close shave when the car skipped sideways towards the barrier braking for the harbour-front chicane but just managed to save the car.
And Hamilton's Mercedes skipped sideways at Tabac, the seven-time champion managing to keep it out of the wall.
Hamilton complained that his Mercedes was suffering from "crazy" bouncing - a recurrence of the problem was "porpoising" on the straights that plagued them through the first five races but which they hoped had been largely fixed with a new floor introduced in Spain.
Behind Norris, Alpha Tauri's Pierre Gasly was an impressive sixth with a time set on the hard tyres, ahead of McLaren's Daniel Ricciardo.
The Aston Martin of Sebastian Vettel split the Mercedes in ninth place.
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