Roberts dominates day one at Laguna Seca.

Kenny Roberts Jr has given America an early home lead in this weekend's US Grand Prix, by dominating Friday free practice at Laguna Seca.

Roberts, who has already taken his father's Honda powered KR211V to one podium finish so far this season, clocked a 1min 23.951secs best in the opening hour around the revised, resurfaced - and very bumpy - Californian race track, then picked up where he left off in the afternoon session.

Perhaps due to the new asphalt, many of the 19 rider field were slow to improve in the afternoon and, by the halfway stage, Kenny himself was still 0.5secs adrift of his morning time. However, the 2000 world champion went on to set the fastest lap of the day, a 1min 23.859secs, with 42mins gone - and that lap ultimately stood unbeaten to the end.

That performance was greeted with cheers from the partisan crowd - and the noise level went up further when fellow American Nicky Hayden, the MotoGP World Championship leader and 2005 US Grand Prix winner, broke the timing beam 0.266secs slower than KR Jr at the very end of the session to claim second place, having been just eighth fastest in FP1.

Third overall and a fraction slower was the first non-American - and a Laguna Seca rookie no less - in the form of Hayden's race winning Repsol Honda team-mate Dani Pedrosa. True to form, the talented 20-year-old Spaniard carefully set about learning the challenging race track in the morning, setting only the eleventh fastest time, before improving by 1.117secs in the afternoon - on a day when five riders failed to even beat their morning best.

Among those was world champion Valentino Rossi. Rossi was the top non-American one year ago, finishing third behind Hayden and Colin Edwards, and hoped that his 2005 experience would benefit him this time around. However, while the Italian superstar was a promising fifth this morning, he could only take his Camel Yamaha to eleventh this afternoon - and eleventh overall - after lapping 0.2secs slower.

Another Italian, Marco Melandri, faired much better - setting the sixth and fourth fastest lap times to claim fourth overall around a racetrack he thoroughly enjoys, but struggled at last season.

Arguably the biggest surprise of the day - aside from Rossi's lowly position - was the pace of Rizla Suzuki rookie Chris Vermeulen, who held second place for much of the closing stages, until finally being demoted to fifth. The Australian has prior knowledge - and race winning knowledge at that - of Laguna Seca from World Superbikes in 2004, but few would have expected him to outpace local team-mate John Hopkins (tenth fastest).

Fastest of the 'non-improvers' was Edwards, second this morning and sixth this afternoon for sixth overall, while rookie Casey Stoner also failed to better his impressive morning pace - partly due to tipping over in the corkscrew gravel - to leave him eighth. Between them was Konica Minolta Honda's Makoto Tamada, who was taken out by Roberts one week ago in Germany and was just 16th this morning - before making a superb recovery with seventh this afternoon.

After Roberts, lap times were very close with second (Hayden) to tenth (Hopkins) fastest covered by just half a second.

Among those, like Rossi, hoping for a set-up breakthrough overnight will be Ducati Marlboro riders Sete Gibernau and Loris Capirossi - 13th and 14th on Friday - plus the Kawasakis of Shinya Nakano and Randy de Puniet, who were just 16th and 17th. Both teams, like Rizla Suzuki, use Bridgestone tyres and the Friday top four were all using Michelins suggesting that they have so far adapted best to the unknown asphalt.

Full times to follow...

Friday practice

1. Roberts
2. Hayden
3. Pedrosa
4. Melandri
5. Vermeulen
6. Edwards
7. Tamada
8. Stoner
9. Elias
10. Hopkins
11. Rossi
12. Checa
13. Capirossi
14. Gibernau
15. Hofmann
16. Nakano
17. de Puniet
18. Ellison
19. Cardoso