Goosen's victory, his first Down Under, was worth $210,408 and moved him from ninth to first-place on the 2002 European money list. He finished on top of the Order of Merit(money list) last season on the strength of two wins in Europe and his breakthrough major triumph in the U.S. Open in 2001 at Southern Hills.
Sweden's Pierre Fulke, the runner-up in last year's WGC-Accenture Match Play Championship in Melbourne, carded the day's best round of 66. His bogey-free effort lifted him into sole possession of second place at 6-under-par, one shot ahead of world No. 4 Sergio Garcia, the highest-ranked player in the field this week.
Garcia, who won his third U.S. PGA Tour title at the winners-only Mercedes Championships earlier this month, closed with a 3-under 69.
Goosen took a one-shot lead with a 68 in Friday's second round, then distanced himself from the field Saturday with a sizzling 63. The 9-under-par score was good for a course record at the difficult Lake Karrinyup layout, and his 13-shot lead after 54 holes set a European Tour record.
'It felt funny having such a big lead,' said Goosen, who was ranked ninth in the world heading into this event. 'In a way it made things more difficult.'
Nothing less than the collapse of the century could produce a tight race in the final round, but Goosen made it interesting by taking a double-bogey 6 at the par-4 opening hole.
Goosen would need to suffer a lot more of the same to slip back to the pack, however, and he managed to settle down with 11 pars and two birdies before his next mistake - a bogey that was the result of hitting his second shot into the water at the par-5 15th.
Although his tee shot found the rough at the 16th, Goosen showed that he still had some magic left over from the day before. His next shot finished five feet from the hole and he made the birdie putt to return to 15-under.
'After the first hole I thought if things kept going wrong, I was going to have a big problem,' he said. 'However, I got there and by the 17th I was able to relax.'
A wayward drive off the 18th tee led to a closing bogey, but the fact was Goosen had wrapped up the victory more than 24 hours before.
'It was a big problem starting out because everybody was expecting me to win,' admitted Goosen. 'I managed to hang in there somehow and it was nice to pull it off.'
He kept up a tradition of success for major champions in this tournament. Nine of the 11 Johnnie Walker Classics have been captured by majors winners, including Nick Faldo (1990, '93), Greg Norman (1994), Fred Couples (1995), Ian Woosnam (1996), Ernie Els (1997) and Tiger Woods (1998, 2001).
Goosen joined Ian Palmer (1992) and Els as South African winners of this event.
Besides finishing fifth, second and first in his three starts on the European Tour this year, Goosen has tallied 13 top-10s - including four wins - over his last 17 starts dating back to last year's English Open, which was held the week before the U.S. Open.
Els, who began the day tied for second with Garcia at 2-under, remained there with an even-par 72. A near ace at the par-3 17th almost earned the two-time U.S. Open winner his weight in the sponsor's whiskey.
Raphael Jacquelin (68) of France tied for fifth place with Englishmen Simon Dyson (72) and Anthony Wall (72) at 1-under 287, rounding out a total of only seven players to finish the tournament under par.
Full-field scores from the Johnnie Walker Classic