Defending champion and current series leader Lewis Hamilton topped the times for Mercedes in both of Thursday's free practice sessions ahead of Sunday's Monaco Grand Prix.
The 30-year-old two-time world champion clocked a best lap of one minute and 17.192 before a rain shower - and a red flag -- interrupted the afternoon's running to wind up seven-tenths of a second quicker than Mercedes team-mate and nearest title rival Nico Rosberg of Germany.
Rosberg, who is seeking to complete a rare hat-trick of three successive Monaco Grand Prix wins, had a 'moment' during the morning when he 'kissed' the barriers at Tabac corner and was unable to mount a serious challenge on the impressive Hamilton.
Another German, four-time champion Sebastian Vettel of Ferrari, was third fastest, 1.1 seconds off Hamilton's pace, but ahead of his team-mate Finn Kimi Raikkonen, Russian Daniil Kvyat of Red Bull and the talented young Spaniard Carlos Sainz in a Toro Rosso.
Dutch teenager Max Verstappen continued his extraordinary impact this season by taking seventh in the second Toro Rosso car ahead of a much-improved performance from two-time champion Fernando Alonso of Spain in the troublesome McLaren-Honda.
German Nico Hulkenberg was ninth for Force India and Frenchman Romain Grosjean 10th in the Lotus.
