SUNG Yau-luk celebrated his new job promotion with the biggest victory of his career in the inaugural Hongkong PGA Classic yesterday. Playing over the Diamond-Ruby layout at Discovery Bay, Sung upstaged his better-known compatriots with a one-over-par 72 to claim the $5,000 first prize from the $100,000 fund put up by tournament sponsor Simon Lo. After turning professional three years ago, Sung served his apprenticeship in the workshop at Fanling where he spent most of his time repairing clubs. He also helped to coach junior players and at the start of the month was promoted to the position of assistant teaching professional at the Royal Hongkong Golf Club. Hitting the ball solidly yesterday, Sung also showed that he is capable of posting good scores. His round included three birdies. Sharing second place on 73 were two of the Tang brothers - Discovery Bay senior professional Alex and Tang Shu-wing - with Clearwater Bay's Len Sorensen fourth. Singapore's Bill Fua, who led his team to victory in Monday's Pro-Am, was the leading overseas player in fifth place on 75 followed by Hongkong PGA champion Tang Man-kee and 1992 Order of Merit winner Richard Kan on 76. Meanwhile, Dominique Boulet, Hongkong's most travelled professional, is keeping his fingers crossed for a late call-up into this week's US$180,000 Lexington PGA Championship on the South African Sunshine Tour. In yesterday's pre-qualifying at the Wanderers Club in Johannesburg, Boulet dropped four shots over the closing eight holes to finish with a three-over-par 74. He was one of 19 players required to return to the course to battle for the final 13 spots in the main draw. After a tense struggle, Boulet was ousted at the fourth extra hole. ''I've been named as the third alternate so there's still a chance I will get in,'' said Boulet, who is making his first visit to South Africa.