F1 Monaco GP: Mercedes' Hamilton leads Vettel in first practice

The Mercedes driver clocked a 1m13.425s on Pirelli's ultra-soft tyres to finish 0.196 seconds clear of Ferrari's Vettel on the streets of Monte Carlo.

Max Verstappen, whose Red Bull team was running a T-wing for the first time, set the fastest first sector overall, but lost time in the middle part of the lap and ended up third quickest, the top three split by just 0.346s.

Verstappen spent a lot of the time in the garage after Red Bull spotted a "potential right rear puncture" and called him into the pits, and he did his best time in the latter part of the session.

Drivers wasted little time in the 90 minutes, Ferrari and Red Bull running the ultra-softs straight away, while Mercedes focused its early running on the super-softs.

Vettel was the early pacesetter, but he was deposed when Mercedes swapped to the ultra-softs with just over 50 minutes to go.

Valtteri Bottas and Hamilton traded fastest laps, with the latter clocking the fastest time on the fourth lap of his run.

Bottas ended up fourth, ahead of Red Bull's Daniel Ricciardo and the Toro Rosso of Daniil Kyvat, who was the best-placed driver on the super-softs.

Kimi Raikkonen kissed the barrier at the Swimming Pool but escaped without damage and was seventh, more than half-a-second slower than team-mate Vettel.

Sergio Perez finished eighth, ahead of Carlos Sainz Jr, who like his team-mate Kvyat was on the super-softs, and Esteban Ocon.

Felipe Massa wound up 11th for Williams, 1.192s off the pace, with Kevin Magnussen 12th in the new-look Haas.

Standing in for Fernando Alonso who is competing in the Indianapolis 500 this weekend, McLaren returnee Jenson Button focused his early running on the soft tyre.

The 2009 world champion then switched to the ultra-soft to go 14th quickest, a tenth-and-a-half slower than team-mate Stoffel Vandoorne.

Romain Grosjean, who spun at Sainte Devote but continued, was 15th.

Nico Hulkenberg failed to complete a flying lap, as Renault spent most of the session investigating a problem with the energy store.

Sauber's Marcus Ericsson also failed to get a time on the board after encountering a gearbox problem.

PRACTICE ONE RESULTS: