MONTEREY, California, July 19 - World champion Nicky Hayden will be looking for another good performance at the U.S. Grand Prix starting Friday, although he faces a tough challenge from Australia's MotoGP leader Casey Stoner.

Despite being the reigning world champion, 25-year-old Hayden is only ninth in the series standings with 73 points.

The American qualified sixth last year at the Laguna Seca event, but moved into the lead midway through the final and was never challenged.

Hayden, who's finished third in the circuit's last two races, was also the winner when the MotoGP made its American debut at Laguna Seca in 2005.

Practice will be held on Friday at Laguna Seca Raceway in the MotoGP class as well as in Superbike and Supersport classes, with qualifying for the MotoGP scheduled for Saturday.

The championship race takes place on Sunday. MotoGP 125cc and 250cc division will not be held.

Stoner, 21, who finished fifth in the circuit's last weekend in Sachsenring, Germany, has won five of his 10 races this season and has not finished lower than fifth.

He will be favoured again this week against a strong American contingent and will also try to make up for a disappointing result last year in the U.S. when he withdrew after a crash.

Stoner leads the overall standings with 196 points with five-times world champion Valentino Rossi second with 164 points.

Dani Pedrosa of Spain, last week's winner in Germany, is third with 144 points, and American John Hopkins fourth on 101 points.

A victory earns a rider 25 points, with points reduced to 1 for 15th place.

The 32-lap race on the 11-turn, 3.6-kilometre Laguna Seca circuit takes place during the venue's 50th anniversary season.