The British champion jockey teamed up with local trainer Frankie Lor in the Group One heat, with Glorious Forever promptly away and soon taking on his full brother, Time Warp, for the early lead.
Time Warp's rider Zac Purton was happy to let De Sousa kick on in front and he was still well in control turning for home, with Glorious Forever finding plenty as the race began in earnest with a couple of furlongs to run.
The siblings were still battling it out inside the distance, but while Glorious Forever sealed victory, Time Warp was pipped for the runner-up spot by the fast-finishing Japanese raider Deirdre.
De Sousa said: "I won the battle for the first 300 metres and after that he was in the money.
"I was going so well at 800 metres I thought if anyone was going to take the race off me, it would have to be one of the Europeans. Everything was in my favour with the draw and everything went to plan."
Lor, who also claimed the Longines Hong Kong Cup Sprint with Mr Stunning, added: "It's amazing. For me I think this is my dream. I talked to Silvestre yesterday and I said if he jumped well, get the lead."
Ed Walker, who previously trained the winner in Britain, fielded Stormy Antarctic but he failed to feature in the shake-up and finished eighth of nine runners.
Walker said: "He relaxed great. They just had a nice scrap for the lead for about five seconds.
"Silvestre absolutely nailed it (on the winner). They left him alone and everyone went to sleep in behind like they were going to do another lap.
"He made up a huge amount of ground and ran well. He was not beaten far. There are no excuses really it was just a funny race.
"If it is very soft, he runs over a mile and if it is better over a mile and a quarter. He is very versatile."
