David Ferraris has set emerging stayer Liberator for next month's Group Three Queen Mother Memorial Cup (2,400m) after a strong win in the Class One feature at Happy Valley last night, the trainer heaping praise on his stable staff for turning the 'quirky' four-year-old around. Jockey Tim Clark sat right on the speed and poured the pressure on from the 400m, getting most of the field off the bit and Liberator showed a nice kick in the straight to score by a comfortable 11/4 lengths. The way the gelding, who was 11th in the Mercedes-Benz Hong Kong Derby and then runner-up at Happy Valley over 1,800m two weeks ago, finished the 2,200m indicated the mile-and-a-half of the Group Three on May 6 won't be a problem, especially now that a few kinks are out of the one-time handful's system. 'He will stay all day and is a nice horse for the Queen Mother Memorial Cup, where he should get in with a light weight; he'll be hard to beat with 113-pounds on his back,' Ferraris said. 'He has always been a good horse, but he is quirky, credit must go to my trackwork rider Chris McMullen, he is the only one who rides him. 'When we first got him, he was impossible, he would spin around on the track and we could hardly work him. He sometimes just stops when going at a canter and turns around.' Liberator showed he wasn't totally reformed when he nearly dislodged Clark on the way to the gates with the same trick. 'He tried to turn around, so I just slid off him and started again,' Clark said. Zac Purton nabbed a double, and captured the Jockey Challenge, with wins on Surfer Boy and Master Rio to maintain second spot in the Jockeys' Championship with 43 wins. His success was tempered, however, by the fact he was handed a two-meeting suspension after only just returning from serving another two-meeting ban last night. 'It was obviously a bit disappointing to cop a suspension, but at least I got to put a couple in the back of the net,' Purton said. 'It is hard when you're not riding for a main stable, when you get a suspension so fast after the first one, you don't know if the rides will be there when you get back.' Surfer Boy's trainer Dennis Yip Chor-hong said his horse, which sat outside the lead and grinded his way to a short-head victory, is better ridden with cover. 'From gate eight, that was how Zac was forced to ride him and he was a bit one-paced from there,' Yip said. 'He is best when he can get on the rails from a low draw, inside horses, and then sprint.' Brett Prebble also rode a double, winning Class Fives on Diligent III and Novel Start, who trainer Gary Ng Tik-keung said was ready to string some victories together after breaking through for a maiden at his 13th start. 'He is just learning to race,' Ng said. 'Last season we would take him to the front, like tonight, and he would go crazy and then stop, and if we took him back in the field, he wouldn't race.' 'I think he has got some class, he is a consistent horse and tonight he proved too good.' Francis Lui Kin-wai said Diligent III was 'still a baby' and could progress further after breaking his local maiden status at his 10th try. He said the key, though, was Prebble's heads-up ride, the Australian recognising a slackening pace and latching on to a three-wide trail to come from the rear in the middle stages. 'When they got to the rock and they let down, Brett saw it and got going, he is a good jockey,' Lui said. Michael Chang Chun-wai seemed relieved to win a race with O'Reilly Magic, a seven-year-old with myriad problems who got a great ride from Jeff Lloyd, the soon-to-depart veteran weaving a path from the rear. 'His back was always sore - you couldn't even touch it with your finger - and his action was short in the back. Club vet Lawrence Chan worked out it was because of a fetlock joint issue and gave him the right treatment 10 days ago,' Chang said. Mark Du Plessis rode a treble last Sunday and he continued his solid form with a great ride on the John Size-trained Enabling in the last.