Champion jockey Douglas Whyte wrapped up a four-timer at Sha Tin yesterday on Ivan Allan's four-year-old Aucash but the jury is still out on just how far the promising horse will go. Whyte dominated the National Day card with wins on Green Diamond and Joint Peace for Alex Wong Yu-on and Admiral for Francis Lui Kin-wai earlier in the day before Aucash made it four in the eighth event. 'Riding any winner is great but four on a day is always special,' Whyte said after surging back to join Felix Coetzee as co-leader for the championship he won so brilliantly last season. 'I was especially happy to win two for Alex, it's a pleasure to ride for him. His horses feel good in the mornings and he's producing them well on raceday. He's a good, patient trainer and he gets them right and fit before they step out to race.' Aucash, an expensive half-brother to former Australian champion Saintly, again looked unconvincing in his neck victory but Whyte believes there is plenty of upside to the four-year-old. 'There was something more there, I believe,' Whyte said after Aucash had appeared to be flat out until the rider sat up in the last couple of strides. 'He wanted to look about near the line, so I eased off him and he seemed to enjoy that. He's still a big baby. Sure, I don't know if I would have really liked the others to really put it to him in the very last bit but there was something there. It was only his second run back and it's typical of how Ivan trains his horses - Aucash hasn't really been squeezed fitness-wise. He's a big, gross horse and I'm sure he will improve.' Whyte said the tempo of yesterday's race suited Aucash, who may eventually be better at longer trips. 'It was a good gallop all the way around which helped him,' he said. 'I think at the moment probably 1,600 to 1,800 metres is his best but as he progresses hopefully he will get further.' Whyte opened the card with a hollow victory on debutant Green Diamond after the four-year-old travelled easily on the speed and scooted away to win in very fast time. The jockey had put in a great deal of the groundwork at the track with Green Diamond and was pleased to see his efforts rewarded. 'Green Diamond won with authority and he is a young horse with some scope,' Whyte said. 'He will improve with racing but we mustn't get too carried away with him - there was not much depth to the race. Likewise, I thought Admiral in the fifth race was a good effort under a big weight but his race didn't look strong either.' The win by Green Diamond was another in the successful path developing between Wong's Sha Tin stables and the Ballarat base in Australia of former Hong Kong jockey Patrick Payne. 'There is no fluke about buying winning horses in racing. I know Patrick very well and I tell him to call me any time he thinks there is something coming up which might be worth looking at,' Wong said. 'He rides them in track gallops and he can tell me how well they go. This is also how we bought Telecom Babe. You need to buy horses this way - it's expensive to buy them without knowing if they are any good.' During last week, Payne successfully bid A$250,000 on a Danehill two-year-old sold at Sydney's Breeze Up sales and destined for Wong's stables here. Wong's second winner, Joint Peace, was having his fifth start in a race, winning the seventh event impressively but has been a difficult assignment due to a weak constitution. 'He doesn't have problems so much as he is a bit weak,' Wong said. 'He takes time to get fit and when he is fit you have to run him because you don't know how long he will keep going.' Joint Peace is a son of Maroof, who sired the winner of last year's Victoria Derby over 2,500 metres in Australia. Wong said that despite his brilliant pace, he didn't believe Joint Peace was strictly a short-course horse and he would be tried over further. 'Maroof horses are not really sprinters,' Wong explained. 'But right now, Joint Peace is too weak to try in longer races. As he gets older and he matures physically, then I would like to try him over further.'