Practice of F1 race - Rosberg and Mercedes on top in Monaco

Monaco resident Nico Rosberg ruled Thursday morning's opening free practice session on the streets of Monte Carlo, pipping Ferrari's Fernando Alonso by just 0.087s as one second covered the first eight cars.

The German lapped his Mercedes in 1m 16.195s, which resisted the Spaniard's best effort of 1m 16.282s. Right at the end Romain Grosjean pushed himself up to third on 1m 16.380s for Lotus, deposing Ferrari's Felipe Massa (1m 16.394s) and Mercedes' Lewis Hamilton (1m 16.469s).

Massa caused a minor stir when he cut into the pits across the bows of Marussia's Max Chilton, while Hamilton had a moment when he ran wide at Ste Devote. The biggest incident befell Adrian Sutil, however, who spun his Force India through 270 degrees at the same corner. His rear wing brushed a barrier but he made it back to the pits for checks.

Pastor Maldonado gave Williams' spirits a boost with the sixth-fastest time of 1m 16.993s on a track on which he always goes well, while 2010 and 2012 winner Mark Webber was Red Bull's leader on 1m 17.020s. His team mate, Sebastian Vettel, was only 10th, on 1m 17.380s. Between them were the modified McLarens of Jenson Button and Sergio Perez on 1m 17.129s and 1m 17.378s respectively.

Kimi Raikkonen was down in 11th place for Lotus on 1m 17.509s, chased by the Force India duo of Paul di Resta on 1m 17.548s and Sutil on 1m 17.625s.

Nico Hulkenberg failed to break into the 1m 17s for Sauber, having to be content with 1m 18.193s to head Toro Rosso's Jean-Eric Vergne on 1m 18.454s, team mate Esteban Gutierrez on 1m 18.754s, and Valtteri Bottas on 1m 18.830s in the second Williams.

At the back, Toro Rosso's Daniel Ricciardo set his 1m 19.067s early on before settling down to long-run work, as Giedo van der Garde was again Caterham's leading runner on 1m 19.203s from team mate Charles Pic on 1m 19.438s. Jules Bianchi was 21st for Marussia on 1m 19.773s, after a visit to the escape road at Ste Devote, as team mate Chilton brought up the rear on 1m 20.225s.

Nobody ran Pirelli's supersoft tyres on Thursday morning, and that, combined with the fact that there will be extra rubber laid down during GP2 practice, means that the times should be significantly quicker this afternoon when the teams sample the softer compound.