World number two Ernie Els is confident the back injury he suffered three weeks ago is no longer a problem and he can make a strong defence of his title in the Sun City Challenge which starts today.

Els walked off the course after just nine holes of the World Championship event at Valderrama in Spain earlier this month because of back pain and flew to London for treatment and rest.

But the South African, who won last year's event with a record 25-under-par aggregate of 263, said: "I feel like I'm back to normal again.

"I played golf for the first time on Sunday and there wasn't even the slightest hint of pain. I feel strong, I've had a good year and there's no reason why I shouldn't defend my title."

The Sun City tournament, with its 12man field, has come to be known as `Africa's Major' and from 1981 until 1999 was known as the Million Dollar Challenge because it offered a first prize of $1 million.

But this year the prize has been doubled to $2 million, making it the richest in golf.

European order of merit winner, Lee Westwood, Zimbabwe's Nick Price, who has won the Sun City showpiece three times (in 1993, 1997 and 1998) and Scotland's Colin Montgomerie, the 1996 champion, are among the other leading contenders.

Ireland's Darren Clarke, Thomas Bjorn (Denmark), John Huston (US), Carlos Franco (Paraguay), Stuart Appleby (Australia), Spaniards Jose Maria Olazabal and Miguel Angel Jimenez and Michael Campbell make up the rest of the field.