LOS ANGELES — The left knee feels good enough that Ernie Els doesn't expect anything to hold him back this year.

It is strong enough that he doesn't think twice at the top of his swing how much it might hurt when he shifts his weight. Most of all, he believes it is strong enough to scale a figurative mountain bigger than Shasta.

The 37-year-old South African has laid out a three-year plan to become No. 1 in the world, a spot he hasn't been in 10 years. That seems like a tall order now, because Els' last meaningful victory was two years ago in the Dubai Desert Classic; because he is No. 5 in the world ranking at the moment; and because the guy at the top — Tiger Woods — shows no signs of a retreat.

But on the eve of the Nissan Open, where Els is making his 2007 debut on the PGA Tour, he was reminded that Vijay Singh was No. 7 in the world when he set his sights on No. 1, and the Fijian got there two years later.

"Well, the one thing going for Vijay back then is that Tiger was changing his swing," Els said with a smile. "Vijay came through. In all due respect, Vijay won how many times? He won nine times in that year. It just shows you what you have to do to beat this guy. Vijay showed us the way. That's the kind of golf you have to play to become No. 1.

"It's not like Tiger is going to sit back and listen to all of this and not hit another golf ball. He also wants to become better and win more tournaments.

"It's a huge mountain you've got to climb," Els said. "But that's what I want to try to do."

He is taking baby steps at the moment.

When last seen on U.S. soil, the Big Easy made a marvelous up-and-down from 100 yards to qualify for the Tour Championship, although he stalled at East Lake to go a second straight year without a PGA Tour victory. He did conclude the 2006 season with a victory at the South African Open, his only trophy of the year.

And he started this year in the Middle East with a runner-up finish in Dubai and a third-place finish in Qatar.

Els is part of a strong international group that has turned the Nissan Open into the strongest field to date on tour, with 11 of the top 13 players in the world ranking competing at Riviera. Only two Americans (Jim Furyk and Phil Mickelson) are in that group.

Els won here eight years ago, holding off a spirited rally by Woods and David Duval. Els returns this year to find blue skies and firm greens, which should put a premium on well-placed tee shots to set up the proper angles to attack the flag.

And he won't have to worry about Woods, not this week, anyway.

In perhaps the most peculiar statistic of the young season, Woods has played only one time on the PGA Tour this year — a victory three weeks ago at the Buick Invitational, for his seventh straight on the PGA Tour — while Mickelson is playing his fifth in a row. Lefty won convincingly last week at Pebble Beach, and is eager to try out his improved driving on the fairways of Riviera.