MAYBE it is because he is working his horses a bit harder than a number of other trainers that it seems that so many of the Derek Cruz team seem to be in good form if their work is anything to go by. Or maybe it is because they are in good heart that he is working them a bit harder. Whatever the reason, a number of Cruz's horses impressed at yesterday morning's Sha Tin trackwork session. None more so than the improving Ming River who, like the more illustrious River Verdon, is a son of Coronation Cup winner and Arlington Million second, Be My Native. What they do appear to have in common is an ability to stay well. Last time out Ming River looked to find a mile on the short side when staying on resolutely close home to run a creditable third to Highland Laddie. He did not get into top gear until the final 200 metres and looked to be crying out for a move to 1,800 metres at least and possibly 2,000 metres. Yesterday he worked a strong circuit of the all-weather with his more speedy stablemate Bold Win and was moving much the stronger of the pair as he came up the home straight. Ming River looks to have progressed nicely since his last start and is an interesting quinella customer in tomorrow's fifth event. Derek Cruz has taken over the training of African Prince from Ivan Allan and seems to be doing a very fine job with this problem horse who has ability but also a great deal of temperament. Yesterday he worked strongly and well and it will be intriguing to see how he behaves when next sent to the barriers. Aurora Spirit never really fulfilled his potential last season but that was the case with so many horses and has to be in part due to the 'flu virus which bedevilled racing for so long. He has not been back in full work for too long but he has been going fluently and yesterday had too much pace for stablemate New Leaf. There was also strong work from the Tony Cruz-partnered Fashion Delux who will be his first ride back for his brother when they step out for the Class Five sixth event at Sha Tin tomorrow. Yesterday Fashion Delux matched strides with Longain, who appears to be returning to a semblance of his old form which would make him a very well handicapped sprinter. Star Greeting, a short head second to Highland Laddie when Ming River was third, was another regular Tony Cruz mount to look on excellent terms with himself yesterday morning. So should Peter Tse Yan-sid's Truly Easy who has run two good seconds on each of his last two starts. And then there was an eye-catching piece from the Brian Kan Ping-chee triumvirate of new horses, Grassland Star, Evergreen Light and Medic Supreme. Grassland Star is the potential smart sprinter out of these three.