Dustin Johnson ready for long game in US Open double quest

World number one Dustin Johnson is preparing for a battle of the big-hitters as he defends his US Open title next week on what is set to be the longest course in major championship history.

Johnson, who clinched his first major victory at Oakmont last year, has been installed as the favourite for the tournament, which is being held at Erin Hills in Wisconsin for the first time.

At 7,741 yards, the challenging par-72 layout outside Milwaukee will be the longest course in the history of major tournament golf.

United States Golf Association officials say the yardage may fluctuate, depending on adjustments to the set up which will be made based on the firmness of the ground and wind conditions.

But for Johnson, one of the longest hitters in golf, Erin Hills' potentially intimidating length augurs well.

The 32-year-old was perfectly positioned to win at Chambers Bay in 2015 -- until this year the longest US Open course in history -- only to three-putt on the 18th green of the final round to gift Jordan Spieth victory.

Yet he recovered from that setback to win at Oakmont last year, finally shaking off his majors jinx after a string of near-misses.

Johnson, who missed this year's Masters at Augusta after a freak accident on the eve of the tournament, revels in the US Open's reputation as the toughest test in golf.

"It's just a very, very difficult tournament to win," Johnson said. "It's always tough. Deep rough, greens are always firm and fast, generally. It's just a tough tournament to win."

- Tougher the better -

This year promises to be no different. Erin Hills, which opens and closes with two monster 600-yard par-fives, is in keeping with the US Open's most demanding traditions -- and Johnson couldn't be happier.

"I like really tough golf courses," he said. "I tend to focus more and play better. I like knowing par is a good score for some reason. I don't know why. I play better when I'm playing for pars."

But the prospect of another intimidating US Open course is not to everyone's liking.

Both 2016 venue Oakmont and 2015 hosts Chambers Bay attracted criticism, and Australia's Adam Scott believes the USGA is under pressure to deliver a controversy-free event this year.

"They're going to have to try to run a really good event," Scott said. "The ball is in their court; they control it all. Hopefully they get it right this time, just from a playability standpoint," the world number 12 added.

"Let's just have something that's a challenge and interesting, not just playing brutal (golf)."

With Tiger Woods still struggling to resurrect his career as he recovers from back surgery, and Phil Mickelson likely to skip the tournament to attend his daughter's high school graduation, this year's US Open could in some respects mark the end of an era. If Mickelson fails to show as expected -- he retains a tee-time despite vowing not to attent -- it will be the first time since 1994 that neither player has featured in the first round.

- Next generation -

Mickelson and Woods' twin absence clears the way for the next generation of golf stars to shine.

World number two Rory McIlroy, who won the US Open in 2011, has declared himself ready despite a frustrating season dogged by niggling injuries.

The Northern Irish star has played only one event since the Masters in April after a rib and back injury forced him to withdraw from the BMW PGA Championship at Wentworth.

"I am ready for Erin Hills and looking forward to playing there for the first time," McIlroy said.

"The last few weeks have obviously been frustrating but it was important I got back to a level of fitness where I felt like I could give myself the best possible chance at the US Open."

Many pundits believe that Erin Hills could be perfectly suited to one of the brightest emerging talents, the brawny 22-year-old Spaniard Jon Rahm, the former amateur world number one.

Rahm, who turned pro in mid-2016 and claimed his maiden PGA Tour win at the Farmers Insurance Open at Torrey Pines in January, has impressed Mickelson with his assured transition to the pro ranks.

"Every part of his game is a strength," Mickelson said in January. "I think he's more than just a good young player - I think he's one of the top players in the world."

Rahm likes his chances too.

"I think my game is pretty suited to the US Open," he said in a recent interview. "It's a really big deal to be precise off the tee, which I am. I've got a good short game and good feel with the putter, too. It's one I could win."