Lewis Hamilton finished fastest in the opening practice session for the Monaco Grand Prix.
Hamilton, who withdrew from his media commitments on Wednesday in the wake of Niki Lauda's death earlier this week, was six hundredths clear of Red Bull's Max Verstappen.
Hamilton's team-mate Valtteri Bottas finished third. Charles Leclerc and Sebastian Vettel, sporting a Lauda-inspired crash helmet in tribute to the former Ferrari driver, ended the opening running fourth and fifth respectively for the Scuderia.
Mercedes are racing for the first time since Lauda, their non-executive chairman, died in Zurich on Monday night.
Their cars are adorned with the motif, ‘Danke Niki’, whilst team members are also wearing black armbands.
Mercedes have struggled with the slow-speed nature of the Monte Carlo street circuit in recent years — but Hamilton’s early pace suggests they could be the team to beat.
The Silver Arrows head into Sunday’s race having started the season with an unprecedented five one-two finishes.
Red Bull, however, could be hot on their heels. Daniel Ricciardo won at the principality last year, and Verstappen might prove Hamilton's closest challenger.
The Dutchman, 20, has enjoyed an impressive start to the season, and will be keen to build on his strong showing in opening practice after he split the Mercedes cars.
Polish driver Robert Kubica lost control of his Williams on the exit of Casino Square, but despite sliding down the hill, managed to keep his car out of the barriers.
British novice George Russell also said he hit the wall, but appeared to escape without damage. He finished 17th.
McLaren’s Lando Norris, on his debut F1 outing in Monaco, finished 15th.
