Paul O’Sullivan collected his 400th Hong Kong winner on Sunday and he is hoping to add to that total with Back In Black and Planet Star at Happy Valley on Wednesday night.

The New Zealand trainer, who arrived at Sha Tin in 2004, pointed to the usual highlights when reflecting on the milestone – his association with five-time Group One winner Aerovelocity and taking out the 2007 Hong Kong Derby with Vital King – but he also noted a lower-profile victory that was just as important for him.

“It was a great thrill, took a while coming, but I think anyone who can train 400 winners here and survive is going pretty good,” O’Sullivan said.

“This place has been very kind to me, I think my biggest highlight was Aerovelocity in Japan because he was representing Hong Kong overseas and it’s always a long way to go if you get beaten, so that was a big thrill.

“Also, in about my third or fourth year here when things were going poorly, my second-last runner just got me the quota in a Class Four mile, I forget his name now but that was a great thrill and of course, everybody likes to win a Derby if they can.”

Back In Black (Tommy Berry) has won five races for O’Sullivan, but the most recent of them was almost two years ago to the day.

His rating has dropped to a level where he is competitive again, as two narrow seconds in his past four starts shows, and the trainer is hoping the wet weather can help lift him back into the winner’s circle when he contests the Class Three Shan Pui River Handicap (1,200m).

“He’s had two or three runs on rain-affected going and has won every time,” O’Sullivan said.

“I’m not too sure how the track will pan out on Wednesday evening but if the forecast is anything to go by, it could be rain affected. His last run was very good, he’s got to overcome a wide draw so any rain would help him a lot.”

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The trainer has been experimenting with different gear on the six-year-old and is sticking to the blinkers after getting an improved effort when putting them back on last start.

“He’s had them on and off and it was just a matter of trying to get his head around things,” he said.

“He’d become a little bit inconsistent, pretty hit-and-miss – when I expected him to go well, he didn’t and vice versa. He seemed a little bit more focused with them on and let’s hope he can take it into his next race.”

O’Sullivan also saddles up the in-form Planet Star (Derek Leung Ka-chun), who will carry the top weight in the Class Four Hong Kong Racehorse Owners Association 40th Anniversary Trophy (1,650m).

The four-year-old has two wins, a second and a fourth from his past four starts and the trainer expects him to be right in the finish again.

“He’s really found his form now. He was doing a lot wrong in his races – he wasn’t changing leg right – but he seems to have worked it out,” O’Sullivan said.

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“He’s got to overcome a wide gate but he’s got good gate speed, he’ll go forward and he’s good and tough.

“I think in time he’ll cut it in Class Three for sure, particularly given his last three or four runs which have been very consistent. Hopefully, he’ll have to face that after this.”