Singh deposed Woods as No. 1 in the world golf rankings last month. Ernie Els has also moved past the American into second place, leaving Woods at No. 3.
'I think his body and his swing do not match like they did some four or five years ago,' Singh said Wednesday. 'So he has to adjust that. I'm sure that once he figures that out, he'll be OK.'
Singh, speaking on the eve of the Dunhill Links Championship at St. Andrews, Carnoustie and Kingbarns, said the swing has to be adapted as the body develops with age.
'As you get older you have to keep adjusting your swing to your body. Your body does not stay the same,' the 41-year-old Fijian said.
'When Tiger first came on the scene, he was extremely strong. I'm not saying he's not strong now but you do slow down a bit. So the golf swing has to match your body's ability.
'You know, I have adjusted accordingly and for the better and I don't think Tiger has done that. I don't think he has progressed that way.'
Woods, 28, hasn't won a stroke-play event since last year's Amex Championship, a title he failed to defend successfully in Ireland last week. His only victory this year was in the World Golf Match Play Championship.
'You've got to win to stay on top,' Singh said. 'Tiger has not won. I'm sure he'll start winning sooner or later but at the moment I think his focus is elsewhere.'
Woods got married Tuesday in Barbados to longtime Swedish girlfriend Elin Nordegren.
Singh, meanwhile, has won eight times on the U.S. Tour this year, including his last three events. He has won $9,455,566 to surpass Woods' record of $9,188,321 set in 2000.
Singh wants more.
'I'd like to get to 10 in the States if I can,' he said. 'That's my goal. That means two out of my last three tournaments. It's going to be a tall order but I've just won five out of six, so I'm sure I'm capable of doing that.'
'I really feel right now that I can win anything I play in.'
While Singh regards this season as a great one, Els regards 2004 as just a good year, one in which he was in contention in all four majors without winning any of them.
'I think it's turning out to be a good year, a very good year. A great year is winning major championships and separating yourself a little from the others.
'But four wins around the world, it's a very good year for me.'
Els, who won the Amex on Sunday, said he was bothered more by his major event disappointments this year than in 2000, when he was second in majors three times.
'I was only in contention to win one of them, the Masters which Vijay won by two or three shots. The other ones, Tiger was unbelievable,' he said. Woods won the other three majors that year.
'This year was definitely different. This year I definitely felt those losses.'
Els has no chance of overtaking Singh in the rankings this week, but could if he wins the Dunhill and the World Match Play at Wentworth next week. Singh also has to play poorly in both for that to happen.
'I just want to play good golf. I played well last week. The No. 1 spot, if it comes around, it does. I just want to play good golf,' The South African said.
Singh credits his improvement to a vigorous workout regimen.
'My trainer just told me two weeks ago we're going to bump it up next year,' he said. 'I said, 'How much more can we bump it up?' I'm already dying out here, the way he's taken me through two workouts a day.'
Singh said the daily workouts should keep him at the top level of the sport for another five or six years.
'It just helps me so much more with my golf game,' he said. 'I feel so much stronger when I'm playing and toward the end of the week I just don't feel tired. I feel like I can go on as long as you have to go on.'
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