World championship leader Fernando Alonso (Renault) emerged fastest on the opening day of practice for Formula One's most famous race – the Monaco Grand Prix. With the track becoming faster as more rubber was laid down, the Spaniard lapped in 1m 15.835s to pip Michelin-shod McLaren- Mercedes test driver Alex Wurz by just 0.077s.

Drivers from five of Michelin's six competing teams completed a clean sweep of the top ten positions. David Coulthard – twice a winner here in the past – was third fastest for Red Bull Racing, ahead of Giancarlo Fisichella (Renault), Juan Pablo Montoya (McLaren), Spanish GP winner Kimi Räikkönen (McLaren), Vitantonio Liuzzi (Red Bull), Felipe Massa (Sauber), Ralf Schumacher (Toyota) and Ricardo Zonta (Toyota).

Minardi driver Christijan Albers was the first driver to fall foul of Monaco's unrelenting barriers. He crashed exiting Casino Square with 20 minutes of the second free practice session remaining. Minutes later, Red Bull test driver Christian Klien – an impressive third fastest this morning – spun into the guardrail on the opposite side of the track. Both cars sustained frontal damage.

Felipe Massa (Sauber) inflicted the most serious damage to his car. The Brazilian crashed at Ste Dévote in the closing moments of free practice.

Although Pedro de la Rosa was originally scheduled to conduct McLaren's Friday test duties in Monte Carlo, the team implemented a late change and nominated Alexander Wurz, its other regular tester. The two will alternate the role for the balance of the season.

Jarno Trulli (Toyota/Michelin), who won the 2004 Monaco GP for Renault, was 13th fastest today.

Pierre Dupasquier, Michelin motorsport director: "There are two key factors about the opening day in Monaco. Firstly, there is absolutely no margin for error and drivers tend to be a little conservative initially, while they reacclimatise to the surroundings. Secondly, the track is always very dirty at the beginning of the weekend and lap times came down considerably as conditions improved during the course of the day.

"We have two tyre compounds available for our partners this weekend and both have performed very well in hot, testing conditions. Speed over one lap is all very well, of course, but we need to make sure we have both pace and durability on Sunday. From what we have seen during several long runs today, we seem to be in good shape on both fronts. Our engineers will pore over all the data very carefully but it is quite possible that both Michelin tyre options will be used in the race.

"Several Michelin teams have the potential to challenge for victory – and that is a source of immense satisfaction."