Casey Stoner completes a perfect sweep of Friday practice at Laguna Seca; seven Bridgestone riders in top ten during both sessions.

MotoGP world champion Casey Stoner completed a crushing performance on day one of the US Grand Prix at Laguna Seca by breaking his own lap record - set during morning practice - on his very last lap of the afternoon session.

Stoner, who sat 0.764secs clear of world championship leader Valentino Rossi by the end of FP1, looked to lose some of his advantage during the first half of the warmer afternoon session - which saw Rossi within 0.2secs of the Ducati Marlboro rider by the halfway stage.

That slim margin continued to separate the top two when the session was red flagged, with 21 minutes remaining, after Kawasaki's Anthony West lost the front of his ZX-RR at high speed on the entry to turn three. West walked away but a section of airfence needed to be repaired, forcing a 20 minute stoppage.

When the session was restarted Stoner instantly delivered a scorching pair of laps to jump 0.844secs clear of Rossi then - just moments after Nicky Hayden had steered his Repsol Honda into a late second position - the Australian finally dipped under his morning time to finish 0.808secs clear of the 2006 world champion.

Stoner, winner of the past three races, is looking unstoppable - especially since Rossi was one of only two riders to lap slower in the afternoon, the other being wild-card Jamie Hacking.

Rossi's 20 points advantage over Stoner thus looks likely to be cut further heading into the summer break, barring a breakthrough from Yamaha, but Rossi might at least feel pleased to be running the same Bridgestone rubber as Stoner after a tough opening day for Michelin.

Hayden was one of only three Michelin riders in the top ten, the others being Colin Edwards in seventh and Andrea Dovizioso in eighth, and the French company will be facing considerable pressure to come up with some overnight ideas.

That said, the lap times behind Stoner were incredibly close with second through to tenth covered by just over half a second - and 15th placed Dani Pedrosa only one second a lap slower than team-mate Hayden.

Pedrosa, riding with fractured fingers and left wrist after falling from the lead of last weekend's German Grand Prix - a mistake that also cost him the world championship lead - improved from 19th and last in the first session to set a pace that would reward him with a world championship point on Sunday.

Meanwhile, behind the top three, rookie Alex de Angelis again underlined his raw speed with fourth place for Gresini Honda while Chris Vermeulen - second at Laguna last year and on pole in 2006 - was fifth fastest for Rizla Suzuki.

Shinya Nakano backed up a shock third in the morning session with sixth in the afternoon, ahead of Edwards and Dovizioso, with Toni Elias the second best Ducati rider in an encouraging ninth for the Alice Team.

Marco Melandri, rumoured to be taking part in his last grand prix for Ducati Marlboro unless he can find a clear breakthrough, was an unexpected fifth this morning, but could only manage twelfth in the afternoon.

Between Elias and Melandri were GSV-R riders Loris Capirossi and wild-card Ben Spies. Capirossi fought forwards from 15th place in FP1, while Spies was eleventh in both sessions, the double AMA champion's progress interrupted by a fall in the morning hour.

Jorge Lorenzo's first day at Laguna Seca was less successful than fellow rookies de Angelis and Dovizioso, the Fiat Yamaha slotting into 13th, ahead of Elias' team-mate Sylvain Guintoli and Pedrosa.

James Toseland knows Laguna Seca from World Superbike, but was a disappointing 16th, although in front of LCR's Randy de Puniet and the two Kawasakis. West's confidence unsurprisingly took a hit after his afternoon fall, while AMA rider Hacking - brought in to replace the injured John Hopkins - slipped from twelfth in the first session to 18th in the second.

2.657secs covered first to last on the afternoon timesheets.

Friday free practice:

1. Stoner

2. Hayden

3. Rossi

4. de Angelis

5. Vermeulen

6. Nakano

7. Edwards

8. Dovizioso

9. Elias

10. Capirossi

11. Spies

12. Melandri

13. Lorenzo

14. Guintoli

15. Pedrosa

16. Toseland

17. de Puniet

18. Hacking

19. West