Monaco: Ferrari's Fernando Alonso showed his mastery of Monaco on Thursday with the fastest lap in a first free practice session cut short in a cloud of smoke. (Agencies)
The Spaniard, twice a winner in the Mediterranean principality with Renault and McLaren, skimmed the barriers and roared past the moored yachts with a best time of one minute 16.265 seconds.
With the sun shining brightly on the sparkling harbour, Romain Grosjean burnished his hopes of becoming a first French Formula One winner in Monaco since Olivier Panis's unlikely victory in 1996.
Grosjean's time for Lotus was the second best, 0.365 seconds off Alonso's.
"I like Monaco, it's good fun. The car is going well at the moment so let's see what we can do later on. It's important to have a car that you are confident with and work every single details because it makes such a big difference," said Grosjean.
Mexican Sergio Perez, returning to the scene of his big accident in qualifying last year, clocked the third best time of the morning for Sauber with race favourite Lewis Hamilton fourth for McLaren.
The largely incident-free session was red flagged with just over nine minutes to go when Heikki Kovalainen's Caterham blew its engine and filled the tunnel - the fastest point of the circuit - with smoke.
Kovalainen parked up at the tunnel exit as drivers threaded their way through the smoke.
With oil also deposited on the track, organisers decided not to re-start the session.
That left Grosjean's team mate and 2007 champion Kimi Raikkonen at the bottom of the timing screens after the Finn completed an installation lap but failed to set a time.
He then sat out the rest of the session as mechanics worked on his car.
Venezuelan Pastor Maldonado, surprise winner for Williams at the last race in Spain but now among the favourites at a track he loves, was again among the frontrunners with the fifth fastest time.
Ferrari's Felipe Massa, under intense pressure to deliver after scoring just two points in five races, was sixth and 0.578 slower than Alonso.
Red Bull's double world champion and last year's winner Sebastian Vettel, joint championship leader with Alonso, clocked the ninth best time.
Five times Monaco winner and seven times world champion Michael Schumacher damaged his Mercedes's front wing when he rode the kerbs at the swimming pool complex and was 11th fastest.
Monaco: Ferrari's Fernando Alonso showed his mastery of Monaco on Thursday with the fastest lap in a first free practice session cut short in a cloud of smoke.