Els must beat two of last year's Major winners

The South African said he had recovered from an illness that "definitely was not bird flu", after being treated on the course by a doctor on Monday.

World number three Els is tipped to win Thursday's �1.1m event as the only player in golf's top-20 in the field.

But compatriot Trevor Immelman will be out to take his title as will British pair Nick Faldo and Colin Montgomerie.

Second Thai boy dies of bird flu

Els had been on holiday in Thailand when he fell ill, having eaten several chicken dinners before news spread of the bird flu outbreak.

The way I hit the ball yesterday, I felt quite comfortable Ernie Els

He has now sworn off chicken, vowing to eat a lot of burgers instead.

"My stomach wasn't all that great but I'm over that now. I had a shot from the doctor and now I'm looking forward to the week," said Els.

"The way I hit the ball yesterday, I felt quite comfortable."

Els won his second Johnnie Walker Classic title in Perth in 2003 and is looking to keep his momentum going after winning the Sony Open in January.

Els retains Hawaii crown

"It's always difficult to defend. It creates a bit of extra pressure. I defended successfully in the Sony and it will probably help me this week," he said.

Els' winning total of 29-under-par at last year's tournament was the lowest winning score to par ever recorded on the European Tour.

But the South African warned against complacency before an event that also includes two of last year's Major winners, Ben Curtis and Shaun Micheel.

"I'm not going into the week trying to win on Thursday. I'll take it day by day."