DIAMOND Coast was sensationally disqualified after winning the seventh event when international riding star Damien Oliver weighed in 1.2 pounds light during high drama at Sha Tin last night. In the process, some $5.5 million in win and place bets went down the plughole amid angry scenes outside the weighing-room as two irate local punters stood shouting at Jockey Club officials demanding their money back. But the race-meeting stewards had no option under the Rules of Racing but to disqualify the Neville Begg-trained four-year-old, the 5.9-1 second favourite who passed the post an emphatic 13/4 lengths to the good of Wang Tak Supreme. Philip Johnston, the Jockey Club's director of racing, explained: ''There is a discretion of a pound already built into the Rules. Once a rider weighs in more than a pound light the Rule then states that he shall be disqualified. ''There are no ifs or buts or maybes about it. He has to be disqualified and it doesn't matter if he won by eight or 10 lengths.'' Oliver agreed with the Clerk of the Scales verdict that he weighed in light by 1.2 pounds and explained that he had been wearing a sweat jacket and had urinated between weighing out for the ride on Diamond Coast, who was set to carry 134 pounds. ''I was wearing a sweat jacket as I had a fairly light ride coming up in the last. ''A combination of that and going to the toilet is probably the explanation,'' Oliver said frankly, having given Diamond Coast just about the perfect ride. ''It is a real disappointment as the scale was flickering between a pound and 1.2 pounds light before settling on 1.2 pounds.'' The stewards found there had been no intent in Oliver's actions and took no further action. The bitter irony for form students is that Diamond Coast had very much caught the eye at Happy Valley last time out when fourth to Ocean Pride without being put in the race. He went down as a horse to bet next time and now this has happened for his luckless supporters. Conversely, John Moore's Wang Tak Supreme may have been doubly lucky to get the race. As well as benefiting from Diamond Coast's misfortune, some astute race readers felt that he had hampered favourite Gold Capture so badly that Gold Capture would have finished in front of him without the interference. Under this reading of the race, Wang Tak Supreme would have been liable for demotion but the race-meeting stewards found the scrimmaging did not warrant a further change to the placings. Begg had earlier been dealt another cruel blow when his faithful old servant Clear Spray broke a shoulder and had to be destroyed after the fourth event. Then Eminence had to be pulled up in running after his saddle slipped during Diamond Coast's race while apprentice Raymond S. M. Tam was lucky to limp away from the track with no more than a badly bruised left leg after a crashing fall from Mustang in the last. ''I don't know whether I will be able to ride on Wednesday,'' said Tam who just over a week ago suffered a bad fall at trackwork when Happy Go Lucky collapsed and died. The on-course highlight was provided by Gary Ng Ting-keung's Sure Win King who came late under a superb ride from Greg Childs to snatch victory from Patrick Biancone's Hong Kong Supreme in the feature $1.7 million Sha Tin Vase. Sure Win King will be aimed at the Derby next season and, given that he was conceding seven pounds or more to a quality field, he is likely to be a very live contender come next February. Trainer Ng is only too well aware of the particular riding tactics that need to be adopted with his son of Straight Strike. ''He has to be held up. He has shown this on each of his three wins,'' stressed Ng who also pointed out that there is plenty of stamina on the dam's side to Sure Win King's pedigree.