FOR much of Ernie Els's career, the enemy has been clearly defined in the centre of the crosshairs. He has hardly ever had to look over his shoulder because Tiger Woods has invariably been a step ahead. But this week, as Els returns to the tournament, and to the place, where it all started, the enemy might well be from within.

If the 24-year-old boy in the man's body, who survived the steaming heat of Oakmont 13 years ago to win a first major title, is just a memory, Els could now do with a touch of that innocent ambition as he attempts to revitalise a faltering game.

"At that age, there's not too much fear around. You haven't had that many disappointments, " he said recently of his play-off victory over Loren Roberts and Colin Montgomerie in 1994. "When you feel confident, you know you can do it. So that was going to be my first win of many, that's the way I thought about it."

And it was the first of many.

A second US Open triumph three years later and a British Open in 2002 are included in his total of 61 wins worldwide.

Ranked at number five in the world, and still someone who swings the club with a sublime mix of power and elegance, he continues to rub shoulders with the elite.

Against that, his last success in America came in 2004, and his two most recent wins were on home South African turf where the quality of the fields left much to be desired.

"If I want to make something happen, I've got three years, " he said earlier in the season.

The something meant winning a few more major titles, and displacing Woods as world number one.

Els has always been a deceptive character. Laidback, languid, a barbecueand-beer sort of guy who has never allowed himself to become obsessed by his job.

Yet, beneath the genial mask, there has been the sharpest of competitive edges.

Now though, there is a perception that the edge might have been blunted. With his family, his course-design business and his winery, there are questions over the three-yearplan. If the remarkable talent remains, the desire might have diminished.

Because as Els retraces his steps at Oakmont, the doubters would say he is damaged goods. Damaged because of the serious knee injury which has compromised the weight transfer in his swing, and damaged because of the Tiger Woods effect.

On holidays in the Mediterranean in 2005, he tore the cruciate ligament in his left knee in a tubing accident.

After surgery, and several months of rehabilitation away from the game, he returned to competition before the end of the year. "I definitely came back very early after the injury, but at the time I thought it was the right thing to do, " he admitted. "I probably could have waited a bit longer."

It was obvious to his coach, David Leadbetter, that he was compensating for the weakness which was still present in the knee. "Leadbetter wants me to swing a certain way and he really feels I'm doing some things a lot differently, " Els explained. "We've worked together on solving a couple of the problems, but it has definitely come from the left knee.

The better I'm getting physically, the more I can start swinging the way I used to."

By his own high standards, he struggled in 2006 when even the untutored eye could discern a problem with the knee. If it has been less evident this season, four top-10 finishes on the European Tour and two on the PGA Tour to date are not performances he would necessarily want to shout about.

Neither was his brief appearance at the Masters where he missed the cut for the first time at a major since the 1999 USPGA Championship. Before the tournament, he was asked how he was going about trying to rekindle the fire. "Play your game, remember how your first success came. It happened because you believed in what you were doing. For a while, Tiger took away that belief, and it cost me several chances."

After rounds of 78 and 76 on a course which for a few years he and Woods had positively owned, that belief was shaken once again.

The Johnnie Walker Classic in Thailand in 1998 was probably the first time Woods got in his head. Going into the final round, Els was eight strokes ahead and Woods was asked if anyone could catch him. "I can, " he replied. When the exchange was relayed back to Els, the response was dismissive. "What's he on?"

But Woods did close the gap, and eventually won at the second play-off hole.

In 2000, the statistics show that he was runner-up in three of the majors, but in the two that Woods won, Els might as well have been playing in a different tournament. At the US Open, he trailed by 15 shots, and at the British Open, the margin was eight. Now Woods was standing on his throat.

There was redemption a couple of years later at the British Open at Muirfield when following the relief of surviving a chaotic four-man play-off, he admitted to have chased Woods too hard for too long. However, the most bitter of his disappointments were yet to come.

He could have, maybe even should have, won the Grand Slam in 2004. He signed for a glorious final round of 67 Augusta only for Mickelson to deprive him with a birdie at the last. He was just two strokes behind Retief Goosen going into the Sunday of the US Open but slumped to an 80. He lost out in extra-time to the unknown Todd Hamilton at Troon, and then missed the play-off at the USPGA by one shot.

It just might have been the season when it was meant to happen for him because, perversely, Woods was never a factor in those four majors.

"After 2004, there's definitely been a slide in my performance, " Els later reflected.

And Woods was back to cast his long shadow once again last year at Hoylake.

Tied for second place with Sergio Garcia and Chris DiMarco, one behind Woods, before the final round, Els eventually trailed in by five. In the Woods era, no two players have been more affected by the world number one's dominance than Els and Garcia.

It's not that he has been attempting a comeback or anything like that, but in an effort to refocus, Els has moved his business to Chubby Chandler's ISM, he has switched equipment companies from Titleist to Callaway, and he fired his long-time caddie Ricci Roberts and replaced him with JP Fitzgerald.

Maybe Oakmont, the scene of his first triumph, will represent the new start he has been searching for. "It was obviously a huge breakthrough for me. It was almost like a bit of a shock the way it happened, " he said recently of that first US Open success.

"I was young, but believe me, you'd rather win something like that at an early age. I see now how tough it is to win a major."

He didn't expect anything in 1994, however, this week, he might expect too much. There are doubts over Ernie Els as a future major champion. However, at 37, when he should be in his prime, the most relevant doubts are probably his own.