MARANA, Ariz. - The remaining top four seeds went down, and so did the defending champion.
The often-unpredictable Match Play Championship more than lived up to its reputation in a topsy-turvy second round at Dove Mountain on Thursday. An event already minus Tiger Woods and Phil Mickelson sent several of the world's best to an early exit.
Lee Westwood, Jim Furyk, Martin Kaymer and Rory McIlroy - seeded second through fifth - were among the losers. Defending champion Geoff Ogilvy was beaten by Colombian Camilo Villegas 2 and 1.
Top-seeded Steve Stricker lost Wednesday in the first round.
The highest remaining seed is England's Paul Casey at No. 6. Casey, the runner-up a year ago who won the World Match Play Championship in England in 2006, swiftly dispatched Canadian Mike Weir, 5 and 4.
The field was narrowed to 16 for today's third round, and it includes former Augusta State All-American Oliver Wilson.
Wilson, seeded 37th, beat McIlroy in 20 holes in one of the many upsets. He'll take on Luke Donald today.
"It's definitely different than the NCAA (basketball) Tournament, where there's a pretty big discrepancy between one and 16," said Nick Watney, who beat Westwood 2 and 1.
"But like you saw, Steve Stricker won two weeks ago and lost yesterday. So it's a crazy format."
The final 16 features five players from the United States, three each from England (including Wilson) and South Africa and one apiece from Colombia, Spain, Japan, India and Thailand.
"We had nine Englishmen in the field, which was impressive," Casey said. "I mean, obviously it was because of Tiger and Phil not being here. But I think that puts a little extra sort of emphasis. You kind of want to be the last Englishman here."
Westwood, an Englishman, came back from two down to pull even after 13 holes. Watney, in his first Match Play appearance, regrouped to win the par-4 14th and 15th with birdies for a 2-and-1 decision.
Furyk and Kaymer both lost to South Africans.
A 13-time winner on the PGA Tour, Furyk was beaten by Charl Schwartzel 3 and 2. Kaymer, from Germany, also went down 3 and 2, to Tim Clark.
In a meeting of South Africans, Retief Goosen beat Ernie Els in 20 holes.
Among the survivors was Spain's Sergio Garcia, a 2-and-1 winner over Swede Peter Hanson.
Wilson was 2-up through 13 holes and appeared in charge of the match. but he double-bogeyed the par-4 14th when McIlroy made bogey, allowing the Northern Ireland sensation right back in the match.
"I was fuming with myself," Wilson said. "I was not happy at all."
McIlroy then birdied the next hole to square the match, and made a clutch 8-foot par putt at the 18th to send it into overtime.
But on the 20th hole, Wilson nearly holed out from the primary rough for eagle before winning with a tap-in birdie.
"I got lucky, really lucky today," said Wilson .
After becoming the second No. 64 seed in the event's 12-year history to beat a No. 1 seed with his win over Stricker, England's Ross McGowan lost to Ryo Ishikawa, of Japan, 1-up.