Tianchi Monster catapulted himself into BMW Hong Kong Derby calculations at Sha Tin on Sunday and trainer Chris So Wai-yin hopes the four-year-old’s 2,000m form will work in his favour in his bid to get a start in the prestigious race.

Tianchi Monster’s fast-finishing victory in the Class Three Tai Hing Handicap (2,000m) will push his rating up to somewhere in the mid-to-high 80s, putting him in the bottom bracket of Derby hopefuls.

“The owner told me earlier this season that we would aim for the Derby but I couldn’t promise anything, but now he should be [a chance],” So said. “Of course [we want to go to the race], it’s not easy to get a horse to the Derby.”

The win was Tianchi Monster’s third from his past four starts, two of which have come at the Derby distance, and So hopes that, if needed, the Jockey Club will use its discretion to ensure he is in the final field.

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“He is proven at 2,000m, he has got the form,” So said. “I’ll have to speak to the handicappers and let’s see. [Hopefully] they select for the distance, because he is proven twice.”

Zac Purton was the architect behind Tianchi Monster’s win and he echoed So’s sentiments.

“There’s no reason why he shouldn’t be taking his place in the Derby field, we know he can run the distance so he could be an outside chance,” Purton said.

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Tianchi Monster was one of six winners for Purton on Sunday and So gave full credit to the Australian after he sat midfield in the run before finding clear air at the top of the straight and reeling in the leaders on the $2.1 favourite.

“Zac is on fire today. Perfect ride, no complaints,” So said. “We talked before the race with the owner and there is only one thing that we were worried about, and that is that we would get stuck because there is no pace.

“There was not much pace and we also got draw one. But he is a very good jockey so I just let him do his job, I didn’t want to say too much.”

So landed a double on the day, his first of the season, with I Do overcoming a less than ideal lead-up to take out the Class Four Po Tin Handicap (1,600m).

After throwing Purton off on the way to the gates, $2.2 favourite I Do was loose for sometime before the barrier attendants brought him under control, with Purton cutting a forlorn figure as he made his way to the start on foot.

His displeasure was soon forgotten, with I Do digging deep in the straight to nab the leaders in the final 100m, notching his first win at start number four.

“Zac said he heard something from behind, three horses coming, and he just reared up,” So said of his unpredictable four-year-old.

“He was OK on the way, he was quiet then he just heard something from behind, that’s just him. He’s just naughty, he’s not nervous, he doesn’t sweat much, he is just naughty.

“Even when we put the saddle on him, it’s hard to get close to him. I keep walking as fast as we can when we put the saddle on.

“Purton has done a really good job for this horse. You can tell he’s still very green. We know the horse should improve in the future, he just needs time, he’s just a baby.”