Woods brushed off the incident near the seventh green

The world number one asked for it to be cleaned near the seventh green by Williams, who stumbled on a rock.

"The ball got muddy. I handed it to Stevie and he was going to rinse the nine-iron as well," Woods explained.

"He was dipping the towel and slipped on a rock. It was either him or the nine-iron - he chose the nine-iron!"

Interview: Tiger Woods

Initial attempts to retrieve the club failed but Woods soon brushed that off.

The American star, playing his best golf of the three days, birdied the ninth to go two holes clear and he ended with a return of three points from five for the 2006 contest.

Rookie Karlsson birdied the first, but Woods replied with three in the next four to move two up.

Woods drove into the trees down six and bogeyed before the lake drama, but struck a glorious iron to seven feet on the ninth which meant he started the back nine two ahead again.

He had two in a bunker on the long 10th, however, and Karlsson remained only one behind when the next was halved in birdies.

The following three were shared as well, but the Swede drove into the lake on the 15th and put his second in the river at the 16th.

A frogman was dispatched to rescue the nine-iron with Woods keen to use it in a tournament next week.

"We got the club back on 15 so I figured it must have been a European who dived for it," Woods added.