Super Sunny Sing extended his winning run to four, advertised his Hong Kong Derby credentials and delivered the biggest victory of Chris So Wai-yin’s career when he won Sunday’s second leg of the four-year-old series, the Classic Cup (1,800m).

Sent off the $3.4 Classic Cup favourite despite no newcomer to the Classic Series winning its second leg since Ambitious Dragon in 2011, Super Sunny Sing produced his customary late burst to go from eighth entering the straight to first passing the post.

Super Sunny Sing, whom So did not even enter in the Classic Mile because his rating of 67 at the time of the Jockey Club framing its field was too low for him to get into the race, was the second leg of Vincent Ho Chak-yiu’s Sha Tin feature double following Golden Sixty’s Group One Gold Cup triumph.

While Ho, through his association with Golden Sixty, is accustomed to winning Hong Kong’s biggest events, So had not won one of the city’s major races before Super Sunny Sing beat Sword Point by half a length.

“I ran second eight years ago,” said So, whose Redkirk Warrior was a nose second to Thunder Fantasy in the 2015 Classic Cup. “To get a horse to win, I’m very happy. It’s relieved a lot of pressure.”

So praised Ho for the feedback he had provided after Super Sunny Sing completed his hat-trick in a Class Three mile contest at Sha Tin on January 24.

“The last time he won, over 1,600m, Vincent told me the horse seems like he’ll handle further distance. This race has proven Vincent correct,” So said.

“Let’s see how he pulls up. The main thing is to make him happy and sound. We’re targeting the Derby. We won’t change too much on his programme. We’ll make sure he eats well, sleeps well, trains well.”

Ho believed Super Sunny Sing had what it took to go one better than not only Redkirk Warrior but also the Wong family’s Sunny Sing, who placed second to Hello Pretty in the 2006 edition of what was then named the Derby Trial.

“I was always confident,” Ho said. “Chris’ team did an amazing job to keep the horse right. The work rider and the assistant trainer have ridden him every gallop. They’ve done an extraordinary job to keep the horse well. Now we’re aiming for the Derby, so we’ll have to get him to recover.”

Also, Ho spoke about the stark difference between Super Sunny Sing now and just a few months ago.

Ho times things to perfection as Golden Sixty prevails in thrilling Gold Cup

“You press a switch and it’s completely different. He’s improved so much,” Ho said. “When Matthew [Chadwick] won on him [at Sha Tin on December 11], he was still pulling a lot, still a big baby.

“The second start I rode him, it was like he knew how to win. When he stepped up to 1,600m – not pulling at all and giving me a great turn of foot – I knew we had something special. Of course, we’ll see how much he improves. He’s still four, and he’s only started to know what winning is about. Let’s see.”