MARANA, Ariz. -- Bring together the top 64 players in the world and no one knows what to expect.
ACCENTURE MATCH PLAY CHAMPIONSHIP
Especially at the WGC-Acenture Match Play Championship.
Hunter Mahan, the defending champion, was asked Monday to list the top three players who have the best reputation in this format. He made logical choices in Luke Donald, Tiger Woods and Ian Poulter.
Donald, who won this event in 2011, has a magnificent short game and can produce the kind of shots that change momentum in a match. Poulter, the star of just about every Ryder Cup he plays, has such a strong self-belief that he can will his way to wins, as he did at Dove Mountain in 2010. And Tiger, well, is Tiger.
''Just a great player and he doesn't like to lose,'' Mahan said.
Before anyone pencils in a bracket that puts those three players in the semifinals, consider recent history.
Donald was No. 1 in the world and lost in the first round a year ago. Poulter hasn't made it beyond the opening round since he won three years ago.
Woods, the only back-to-back winner of this World Golf Championship, hasn't made it out of the second round since his last win in 2008.
The brackets are set up like they are in other sporting events, whether it's a Grand Slam event in tennis or the NCAA basketball tournament. The difference in golf is that over 18 holes, there's not much to separate No. 1 from No. 64.
It all starts to unfold Wednesday on The Ritz-Carlton Golf Club at Dove Mountain, a Jack Nicklaus design that features massive slopes on the greens and might not be much fun to play if not for the format of match play.
Rory McIlroy is the No. 1 seed and takes on Shane Lowry in the first of two matches between Northern Ireland and Ireland; Graeme McDowell faces Padraig Harrington in the opening round. Woods opens against Charles Howell III, while Poulter faces Stephen Gallacher of Scotland.
Most of the players arrived Monday for practice or to see the golf course.
All of them would like to stick around as long as possible.
''If you get to the weekend, it's one of the most fun weeks of the year,'' Geoff Ogilvy said last week. ''If you lose the first round, it feels like the worst week of the year.''
Ogilvy failed to qualify for the first time since he won in 2006 when it was held at La Costa, though he isn't the only one missing. Retief Goosen ended his streak of playing in the Match Play for 13 consecutive years by not being high enough in the world ranking.
The top 66 qualified because Phil Mickelson (family) and Brandt Snedeker (sore ribs) aren't playing.
David Toms knows both sides of this feeling. It was fun when he reached the championship match against Woods in 2003, and it was a blast two years later when he smoked Chris DiMarco in the finals to win. And then there was the time he lost to Sergio Garcia in the opening round three years ago.
''I lose my first match and then I got picked for drug testing,'' Toms said. ''I said, 'Don't you think you should test the guy who just won?' But it's a great week if you have a chance at the end.''
The tough part, of course, is getting started.
It's not a good feeling to lose early, particularly for some of the international players who have crossed oceans to get here. Such was the plight of Thomas Bjorn one year. He played 14 holes and was on his way back to Europe.
Mahan was asked the feeling of losing the opening match, climbing into the van for a slow, long ride back to the clubhouse.
''You just don't want to be there anymore, unless you win,'' he said. ''Then, you don't have a problem signing anything that anyone wants you to sign. But it's a weird feeling. The van can't move fast enough. People can't get out of the way fast enough. Everything bothers you. And if someone asks you, 'How was your day?' you want to punch them.''
There have been some quick tempers over the years.
Woods, the one year he lost in the opening round as the No. 1 seed, walked down the 18th fairway alone at La Costa with a few thousand people in tow, not saying a word. Ernie Els is known as ''Heisman'' after losing in the opening round -- that's the gesture he once made when he saw a reporter approaching.
A European Tour official approached Pat Perez for a comment after he lost one year. Perez offered three words. Two of them couldn't be printed.
Mahan said of Perez: ''He probably does all the things I think about.''
Good form doesn't always count for much, either.
The past two winners on the PGA Tour in the week before Match Play both lost in the opening round -- Bill Haas to Ryo Ishikawa, Dustin Johnson to Camilo Villegas.
As for match play reputations, Justin Rose might be worth part of the conversation. He won an exhibition in Turkey last year that was medal match play - head-to-head with the lowest 18-hole score winning -- and then did pretty well in that other exhibition, the Ryder Cup.
It was his 35-foot putt against Mickelson on the 17th hole at Medinah that was the most critical toward Europe's stunning rally on the final day.
''I definitely would like to ride that wave of momentum and confidence,'' Rose said. ''There was a couple of matches in Turkey that I pulled off a shot when I had to. Obviously, the Ryder Cup I pulled off a shot when I had to. It's always a bit of fortune to hit the right shot at the right time.''
That's what the Match Play Championship ultimately is all about -- good fortune, and good golf helps create that fortune.
Mahan, who defeated McIlroy in the championship match last year, was asked what he learned about being successful in match play.
''You have to play good,'' he said. ''That's the only thing that matters.''