Marco Simoncelli responded perfectly to criticism over his latest race accident, last weekend at Assen, by leading First free practice for his home Italian Grand Prix at Mugello.

The San Carlo Honda Gresini star, a top-two qualifier at the last five races, is still in search of a first MotoGP podium after falling in four rounds and being penalised for a collision with Dani Pedrosa in another.

Simoncelli moved ahead of world championship leader Casey Stoner by just 0.040sec on his final lap of Mugello morning practice, with Stoner's Repsol Honda team-mate Andrea Dovizioso making it two Italians in the top three.

By contrast, countryman Valentino Rossi - who will take part in his first Mugello event as a Ducati rider without crew chief Jerry Burgess - had a disappointing start.

The 2002-2008 Mugello winner suffered technical problems with both of his Desmosedici GP11.1s, forcing him to park his number one bike and then roll slowly down pit lane after returning to the track with his spare bike.

The problems were reported to be electrical and Rossi finished the session just 13th (+1.793sec), having completed 13 laps - the least of any rider.

Behind Dovizioso were Factory Yamaha team-mates Jorge Lorenzo and Assen winner Ben Spies, creating a top five covered by just 0.377sec.

Monster Yamaha Tech 3 rider Colin Edwards was the lead non-factory bike rider in sixth (+0.823sec) with Pedrosa - making his return from injuries sustained in his tangle with Simoncelli - seventh (+1.117sec) and Rossi's team-mate Nicky Hayden eighth (+1.216sec).

Simoncelli's team-mate Hiroshi Aoyama (+1.642sec) and Suzuki's Alvaro Bautista (+1.671sec) completed the top ten.

Rookie Cal Crutchlow was eleventh (1.696sec) after his first 45-minutes at the track, with lone Pramac rider Randy de Puniet a fraction ahead of Rossi.

Team-mate Loris Capirossi is missing his home event after being injured in qualifying for last weekend's Assen round.

The Mugello circuit has been resurfaced for this weekend's event.

Friday practice (1):

1. Simoncelli
2. Stoner
3. Dovizioso
4. Lorenzo
5. Spies
6. Edwards
7. Pedrosa
8. Hayden
9. Aoyama
10. Bautista
11. Crutchlow
12. de Puniet
13. Rossi
14. Barbera
15. Elias
16. Abraham