Providing Yip with his first triumph in the Classic and Purton's second after Luger in 2015, Massive Sovereign clocked the fastest time in Derby history – 1m 59.85s – since the race distance was changed to 2000m in 2000, bettering champion Golden Sixty's time of 2m 00.15s, set in 2020.

In a thrilling finish, Massive Sovereign  charged from the tail of the field to beat Galaxy Patch by a neck. Front-runner Ka Ya Generation was a neck further back in third place as all three place-getters broke two minutes on the good to firm surface in front of 60,976 spectators.

Formerly known as Broadhurst when trained by Aidan O'Brien in Ireland, Massive Sovereign was having only his second Hong Kong start after having secured a place in the BMW Hong Kong Derby with a stunning debut win over today's course and distance on 3 March.

Backed into 4.4 on the strength of that win, Massive Sovereign sat at the rear of the field before gradually edging closer while tracking Helios Express, who was bidding for a clean sweep of the Four-Year-Old Classic Series after snaring both the Hong Kong Classic Mile (1600m) and the Hong Kong Classic Cup (1800m).

While Helios Express finished eighth, Massive Sovereign emerged from a chasing pack to stymie Andrea Atzeni's daring all-the-way bid on Ka Ying Generation - who threatened to defy his 39/1 odds after sweeping to a five-length lead at the 400m.

Weaving into clear running, Massive Sovereign responded strongly under a desperate Purton with a final sectional of 22.58s to overhaul a courageous Ka Ying Generation, while also defying Galaxy Patch, who clocked 22.40s for the last 400m.

 Hong Kong champion trainer in 2012/13, Yip revelled in the most important success of his career.

"It's very exciting. I think the Derby for me is more important than the championship…but this one for my life is the big one," Yip said.

"He's a very special horse with a very good mind. The last 200m I was very nervous but I rely on Zac. He is the champion jockey in Hong Kong and everything was good with the horse.

"This horse, the first day he arrived in Hong Kong, he (Purton) sent me the video (of Massive Sovereign winning at Leopardstown) and told me he thought he was a nice horse and asked me if he could ride him.

"I've already entered him for (the FWD QEII Cup) at the end of April. I will see how the horse pulls up. If he's good and he improves, I will go this way.

"I'm very happy, it's amazing for my life. What a memory."

Purton described securing the ride on Massive Sovereign – a No Nay Never gelding who won two of five starts for O'Brien – as the fruit of several "sliding doors" moments.

"There are all those sliding doors moments in the season leading up to it. At once stage, I thought I was going to ride Ensued and the owner wanted Ryan (Moore), then I thought I would ride Helios (Express) and I was away when Hughy (Bowman) won on him and then I watched him win the first two legs (of the Four-Year-Old Classic Series)," Purton said.

"I didn't really have a horse for the Derby until this bloke won so, like when I won on Luger, it was a late pick-up ride into the race.

"I feel extremely honoured and privileged to have found such a horse to win it. To win the race itself, it's the most prestigious race in Hong Kong and I've had a frustrating run in this race and a frustrating season, so it's nice to get another big one – and probably the biggest one among the local races overall.

"He's shown us so far that he's the ideal horse here in Hong Kong and he's got such a good attitude. He just takes everything in his stride since he got here. I loved him in the mornings, you love a lot of horses in the morning but they don't turn up on race days – this guy has turned up on race day so far.

"I'm not sure how good he's going to be, only time will tell but he's done a good job so far.

"When the leader was that far in front, and that horse (Ka Ying Generation) keeps galloping - he doesn't stop or give up - he might have tired a little bit but he didn't capitulate, so he made me earn it. I always thought I was going to get close, but how close you can't be sure.

"Once I got to the 200m, I could feel I had his measure."

Purton also struck on David Hayes-trained Ka Ying Rising in the Class 3 Werther Handicap (1200m) and David Hall's Flying Ace in the Class 1 Rapper Dragon Handicap (1200m) to have 83 wins for the season – 27 more than Karis Teetan (56).

 Francis Lui took training honours with a treble, triumphing with Patch Of Theta, Divano and Second To None. Patch Of Theta collected an ISG Bonus of HK$1 million with victory in the Class 3 Ambitious Dragon Handicap (1400m) to give Teetan a brace.

Lui and Lyle Hewitson opened Derby Day in blistering fashion with a race-to-race double. The pair struck first with promising Brave Smash gelding Divano, who easily won the Class 4 Furore Handicap (1200m) before scoring with Second To None in the Class 4 Fay Fay Handicap (1400m).

Ryan Moore and John Size reprised a familiar partnership when Lifeline Express broke through at his sixth start in the Class 4 Ping Hai Star Handicap (1200m) before Frankie Lor's Loyal Bo Bo slotted his second course and distance win under Hugh Bowman in the Class 4 Sky Darci Handicap (1400m).

Tony Cruz slotted a double with Californiatotality in the Class 4 Luger Handicap (1600m) for Brenton Avdulla and The Best Peach in the Class 3 Designs On Rome Handicap (1800m) for Teetan.

Hong Kong racing continues on Wednesday night (27 March) at Happy Valley.