MARANA (Arizona), Feb 23: More top seeds tumbled out of the WGC-Accenture Match Play Championships on Friday, making the word ‘upset’ more a description of the mood of the losers than any shock at the results in golf's most unpredictable tournament.

Former champion Luke Donald, the No 3 seed, was the biggest name to fall in the second round as he suffered his worst loss in 25 matches at this tournament after being pummelled 7 and 6 by American Scott Piercy.

Making his first appearance in the elite World Golf Championships (WGC) event, Piercy will next meet 2001 champion Steve Stricker who edged past fellow American Nick Watney after 21 holes.

Louis Oosthuizen (No 4) and Justin Rose (No 5) never even reached the 17th tee before they were sent packing. They joined Rory McIlroy and Tiger Woods, who both lost on Thursday.

When another wild day ended at Dove Mountain, Masters champion Bubba Watson was the last man standing among the top 10 seeds.

“This game ... it's a toss-up,” Watson said after going 22 holes to beat Jim Furyk. “You can't really judge who's going to win, or bet who's going to win.”

It was the first time since the Championships began in 1999 that only one top-10 seed was remaining after two rounds.

Oosthuizen, a former Masters champion from South Africa, joined the exodus of bracket leaders as he was beaten 3 and 2 by American Robert Garrigus while Rose was also on his way home, falling 4 and 2 to Belgian Nicolas Colsaerts.

Garrigus faces Jason Day who overcame a clutch putt on the 18th hole to beat PGA Tour rookie Russell Henley on the 19th while Colsaerts will next face American Matt Kuchar, who beat Spaniard Sergio Garcia 2 and 1.

Ireland's Shane Lowry showed no letdown after his triumph over McIlroy, advancing with a convincing 6 and 5 victory over Sweden's Carl Petterson. He's the first 64th seed to reach the third round in the 15-year history of the event.

Lowry booked a third-round match against another old friend from Northern Ireland, Graeme McDowell — who finally put away Sweden's Alexander Noren at the 20th hole.

The other giant killer, Charles Howell III, wasn’t so fortunate. After beating Woods on Thursday, he ran out of steam as he was crushed 6 and 5 by Spaniard Gonzalo Fernandez-Castano.

Ian Poulter, the 2010 champion, also advanced with a 3 and 1 victory over American Bo Van Pelt to set up a third-round encounter with South African Tim Clark, who beat Dane Thorbjorn Olesen 3 and 2.

Defending champion Hunter Mahan had an easy time with Richard Sterne to win his eighth straight match, and next faces the last player to beat him in this event — Martin Kaymer, who defeated Rafael Cabrera Bello of Spain.

US Open champion Webb Simpson moved on with a 1-up win over Sweden's Peter Hanson and next faces Fernandez-Castano.—Agencies