Masters champion Jordan Spieth launched his assault on the WGC-Match Play Championships here Wednesday with a comfortable opening victory in the new-look $9.25 million event.

The in-form 21-year-old, fresh from a scintillating start-to-finish victory at Augusta, had little difficulty in putting away Finland's Mikko Ilonen 4&2 at San Francisco's Harding Park course.

It was a sobering reality check for Ilonen, the lowest ranked player in the field who had only traveled to California as a reserve before entering the tournament when Phil Mickelson withdrew from the 64-man field on Sunday.

The new round-robin format of this year's competition means however that Ilonen will stay in San Francisco for at least two more days to play his remaining games in Group Two, which also includes England's Lee Westwood and Matt Every of the United States.

Organizers of the tournament, hoping for a dream finale between Spieth and world number one Rory McIlroy on Sunday, revamped the competition this year to eliminate the possibility of a first round bloodbath.

Previously, defeat in the opening round meant an early flight home. But now the field has been split into 16 groups of four players, with the group winners advancing to the knockout rounds over the weekend.

Sweden's Henrik Stenson, England's Justin Rose and Australia's Jason Day all suffered upset defeats elsewhere Wednesday.

World number three Stenson, the 2007 winner, lost on the 19th hole against Australia's John Senden, ranked 65 in the world.

Rose, in good form after winning the Zurich Classic on Sunday following a second place finish in the Masters, went down 3&2 to Australia's Marc Leishman.

Day meanwhile crashed to a 4&3 loss in Group Seven to Charley Hoffman, ranked 50th in the world. Hoffman cruised to victory, winning 4&3.

There was disappointment too for England's Ryder Cup star Ian Poulter. Poulter, who often thrives in the Match Play format, went down 3&2 to Webb Simpson of the United States.
Source: AFP