ONE-TIME Derby favourite and Queen Elizabeth II Cup winner Star Mark bids to recapture former glory in the fourth event at Happy Valley tonight. The Irish import, who has been with former champion trainer Brian Kan Ping-chee throughout his Hong Kong career, has slipped down the ratings since his heyday but remains a solid campaigner - and a top chance in this Class Three, 1,800-metre event. Said Kan: ''I have always liked this horse. When he came from Ireland I was certain he was the best I had ever trained and he won some very good races for us. ''The owner is a good friend of mine and I always like to win at least one race with him every season. We won the Kwangtung Cup with him last season but it is getting harder every year because the younger ones are now so much better,'' said Kan. But Star Mark is definitely going well and Kan, who has been having a good run with stable jockey Felix Coetzee recently, is convinced his Irish-bred eight-year-old will take a lot of beating. ''He did not have a lot of luck in the run last time and he is better over 1,800 metres anyway. And he doesn't usually have such a light weight so I am sure he will run well. ''Star Mark still enjoys his racing and that is important.'' Star Mark finished only a length away from winner Prince Of Minstrel at his last start and he did have a chequered passage. Although his overall form is better at Sha Tin - he has raced much more often at the New Territories track - he has still acquitted himself well round Happy Valley and this is a moderate event. Tony Cruz, fresh from a glorious Saturday night treble at Sha Tin, could well start favourite on New Leaf but has to combat the bad barrier draw of 10. New Leaf has been an in-and-out performer since arriving from New Zealand but his last run certainly had merit to it. That was over 1,600 metres and New Leaf finished second to Diamond Coast with Miss Piggy in third spot. That is really quite excellent form taken in the context of tonight's Class Three event. Miss Piggy came out off a bottomweight in higher company last time to win quite brilliantly and that has undoubtedly franked the form as far as New Leaf is concerned. And Diamond Coast lost no admirers with his last effort when he made up some ground late. He should be winning again before the end of the season. The one to bear in mind is topweight Oriental Power, to be ridden by Jackie C. K. Tse for trainer Peter Ng Bik-kuen. This is another Irish import for the popular trainer and he has enough form from overseas to suggest he is up to winning in Class Three. Oriental Power is competing tonight on the overlap system and a number of higher-grade horses have won when first striking the lower company. Oriental Power has Irish form substantially similar to that of Smiling with whom Ng came desperately close to winning with again on Saturday night. There is very little between them and if Oriental Power happens to strike his form here then he could win without surprising. He is carrying a lot of weight but the trip would be ideal for him and over 1,600 metres two starts back he was not that far away at the finish. Claimer Raymond S. M. Tam rides Sweet Win for his master David Hill but, strangely, the horse has always gone much better over 1,650 metres at the Valley rather than 1,800 metres. He can stay the longer trip but seemingly it is the Valley version of the mile that suits him best. Said Hill: ''I don't know what it is but his record over this trip at the Valley is very good indeed. He's had a bit of a break since winning for Basil Marcus last time and he should run well.'' The other likely improver in the field is the Darren Gauci-ridden Fortune Ring who was doing his best work at the line over 1,650 metres here last time. Although the New Zealand-bred stayer is half a furlong better in wet ground, he still ran most encouragingly after a break and has clearly come on from that. Fortune Ring is well drawn and Gauci is riding in confident style at the moment and could go very close with this fellow. Rambo is a front-running type but cannot seem to finish off his races, no matter what distance they may be. Maximum claimer Peter W. L. Ho, who is well worth the 10 pounds, is engaged here but Rambo may not be the most resolute of customers and could be found wanting again - despite the weight advantage. New Airport has run a couple of good races over this trip but seems to be out of form and Thor Win ran no sort of race last time when also ridden by Tse Wai-ho who has the mount here.