Webb Simpson, the 2012 U.S. Open champion, stood on the driving range at The Golf Club at Dove Mountain on Monday afternoon taking swing after swing with his 7-iron.

With no more than 100 fans looking on, Simpson sent a ball into the fairway and a grass divot into the seats to his left, which landed in a fan's lap.

"I thought you might want some grass," a smiling Simpson said to the fan.

Welcome to Monday at the WGC Accenture Match Play Championship.

It's not about winning yet. It's not about competition. On Monday, it was all about having fun and getting the feet wet.

The majority of the 64-player field arrived at Dove Mountain in advance of Wednesday's scheduled opening round. A few more will make their way to the course today.

There was a lot of joking, smiles and general good feelings on the course and driving range.

That will likely change today, and the mood will differ. In a format where it can be one-and-done, it will be all business as golfers try to avoid the dreaded first-round exit and ticket out of town.

"You can have just a slightly off day and you can go out in the first round," said Louis Oosthuizen, the No. 1 seed in the Ben Hogan bracket. "It's a weird format. It's a completely different one, where if you have a bad day, you can't come back the next (day) and have a low round to get yourself back in the event."

Oosthuizen, a 30-year-old South African, is a good bet to get past Wednesday.

He entered the week ranked No. 5 in the world, but nabbed a No. 1 seed when Brandt Snedeker withdrew because of a rib injury. Oosthuizen was No. 30 in the world the week of last year's tournament, but shot up the world rankings thanks to a stellar year.

The 2010 British Open champion finished second at the 2012 Masters, losing to Bubba Watson in a playoff. He won the next event he entered - the Maybank Malaysian Open - and was victorious again last month at the Volvo Golf Champions in South Africa.

Additionally, he's finished in the top ten in 13 of the last 27 tournaments he's entered. With a career 1-3 record at Match Play, Oosthuizen, and that No. 1 seed next to his name, are ready to do damage.

"My goal is to climb up the world rankings all the time, and to be a No. 1 seed in the bracket is a great thing for me," said Oosthuizen, who faces Richie Ramsay on Wednesday.

"It keeps me motivated to go even higher. At the moment I'm fifth in the world and I'm trying to see if I can even go higher."

Oosthuizen moved up one spot to No. 5 in the world rankings this past weekend without even playing. That allowed him to pass Justin Rose and secure a No. 1 seed, while Rose fell to the two line.

Rose was also at Dove Mountain on Monday and was out on the course to get some practice holes in.

Like others who have played Dove Mountain, Rose said the greens will challenge him most this week.

"The greens definitely have a lot of movement to them, and you often get pins that are cut on little shelves, three, four-yard shelves," said Rose, who gets K.J. Choi first. "You need to know which side of the green is best to miss to give yourself a chance to up-and-down it."

The other key to having a successful week is staying out of the desert.

No one knows that more than last year's champion, Hunter Mahan, who kept the ball straight and long en route to his first Match Play title over Rory McIlroy.

"This is a course where I feel like you've got to obviously hit the ball in play so the desert is not part of the golf course," said Mahan, a No. 6 seed who faces Matteo Manassero first. "Playing out of the desert, there could be a lot of lost balls or lies that you're not going to be able to really make anything out of."

The other part to playing well is having the no-holds- barred attitude that wasn't present Monday, but will be all week. Losing at Match Play means a long van ride back to the clubhouse - something Mahan and the rest of the field desperately want to avoid.

"The van can't move fast enough," Mahan said. "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 in the face."

If you go

• What: WGC-Accenture Match Play Championship

• Where: The Golf Club at Dove Mountain, Marana

• When: Wednesday- Sunday

• Tickets: Buy at Bashas', call 520-571-0400 or go to www.worldgolfchampionships.com

Contact reporter Daniel Berk at dberk@azstarnet.com or 573-4330. On Twitter @DSBerk.