WHAT a difference a week makes. Last Sunday, Centre Court at Victoria Park was packed to capacity as an adoring crowd watched Michael Chang win a tournament in Hong Kong at last. Yesterday, all the fanfare and hype was absent. Only around 20 spectators were present as the Hong Kong Open Junior Championships came to a close. Perhaps the 3,980 empty seats were a sad reflection of the state of tennis in the territory. Only a ''big'' name can draw the crowds. You could hardly expect to find such a name in a tournament for budding hopefuls. But never mind the lack of punters. What was more upsetting was the absence of a Hong Kong player in the finals of the boys' and girls' singles. Maybe if there had been such a figure, the crowds might have turned up. Sadly, Hong Kong does not have a Patricia Hy, a Paulette Moreno or a Kelvin Ng these days. They did have 10 players taking part in the boys' singles competition. John Hui made the best progress, securing a quarter-final berth. In the girls' singles, the territory had six representatives. Jacklyn Fu was the only one of them to win a match, defeating a fellow-Hong Kong player Natalie Banday. Fu, however, lost in the second round. So without a local player to support, it is not surprising that the crowds stayed away in droves. It must have been galling for Korean Lee Jeong-min and Ludmilla Varmuzova of the Czech Republic to win the boys' and girls' singles titles respectively, yesterday in such sterile circumstances. Lee, a tall, well-built 17-year-old, possessed too much savvy for Indonesian Andrian Raturandang, sweeping to a 6-2, 7-5 victory. Lee took only 69 minutes to wrap up the final. Earlier, Czech teenager Varmuzova had taken the girls' singles title with a 6-3, 7-5 win over Francesca La'O of the Philippines. Like many 15-year-olds Varmuzova sports braces, adores Steffi Graf and would one day like to become a full-time professional. She has a long haul in front of her. She is 27th in the International Tennis Federation junior rankings and 590th on the WTA professional list. ''If I'm good enough, I will one day decide to play professionally full-time. But for now, I will continue to study and play tennis,'' said Varmuzova shyly. She was certainly good enough to overcome top seed La'O, who was perhaps a trifle unfortunate to be on the wrong end of a number of doubtful calls. ''This is the third time I have won a tournament and I'm really pleased,'' said Varmuzova. Her victory yesterday did not earn her a cent. It will only help boost her junior rankings. For the moment, however, her goal is to study in America. An ambition which has cost Hong Kong quite a lot - with most of the territory's budding players giving up the game for studies abroad. Michael Chang's chosen one has been chosen for Hong Kong. Desmond Chan, 13, who American-Chinese Michael Chang picked out as a future prospect during last week's Salem Open, is in the three-strong Hong Kong squad for the NTT World Junior Championships in Bangkok next month. He will join Jason Sankey and Wayne Wong in the boys' team while the girls' team is Cindy Ha, Tong Ka-po and Natalie Banday. Three countries will qualify from the 12 Asia and Oceania teams for the finals in Japan in August. Chang, who hit with Chan at a clinic he conducted in Hong Kong, said: ''He's always in the back of my mind . . . I do remember these things.'' Sankey will also be part of the Hong Kong under-16 team for the World Youth Cup qualifiers in Japan. He will be joined by John Hui and Jamee Wong while Lorraine Ng, Yan Sin-man and Rebecca Hawkes make up the girls' team.