Lewis Hamilton has topped the opening practice session of the Monaco Grand Prix weekend, setting a lap time of 1:12.106.

The world championship leader was only marginally ahead of Max Verstappen in the Red Bull car, who was just over half a tenth down on Hamilton’s time.

Verstappen went straight on at Turn 5 during the session, and struggled to pull the car in reverse gear. The Dutchman received the help of the marshals and managed to get back on his way.

Valtteri Bottas was also close to Hamilton’s time, as the top three were separated by less than a tenth of a second.

Traffic was a problem for many drivers during the session, as they got held up by their fellow competitors while attempting to set a lap time.

Ferrari was further back down on Mercedes and the Red Bull of Verstappen, with Charles Leclerc’s fastest time reading 0.361s down on Hamilton.

Vettel, who is sporting a special helmet in tribute to Niki Lauda this weekend, was over seven-tenths down on Hamilton in fifth place, while the second Red Bull of Pierre Gasly was sixth.

Shortly after the start of the session, both Haas’ were black flagged by the FIA due to the fact there was no communication going from the team to the driver. Both Romain Grosjean and Kevin Magnussen managed to return to the circuit later in the session.

Carlos Sainz failed to set a time and only got out with a handful of seconds left on the clock, as McLaren discovered an issue with his car, believed to be related to the battery.

Renault managed to secure the ‘best of the rest’ spot for the opening practice session, as Nico  Hulkenberg was seventh, just behind Gasly on the same compound.

Despite the communication and telemetry problems that it endured during the session, Haas’ Magnussen and Grosjean ended the 90-minute session in eighth and tenth respectively, with Kimi Raikkonen lodged between both.