Representing the UK, de Sousa’s win was only decided in the final leg.
Australia's Hugh Bowman and reigning Hong Kong champion Zac Purton both failed to register points in any of the four legs, finishing at the bottom of the 12-man list of invited riders from around the world.
Ireland's Colin Keane got his Hong Kong debut off to a flying start in the first leg when having his first ever ride at Happy Valley wth a win on th John Size-trained Special Stars, beating de Sousa's mount Midnight Rattler.
De Sousa struck in the second leg aboard Jimmy Ting's Glory Star.
US star Javier Castellano threw down a challenge on Good For You but Glory Star had too much in reserve and held on for a convincing win.
Keane picked up more points for third on C P Power.
Vincent Ho got his name on the scoresheet in the third leg, getting up close home on Manfred Man's Little Island when he ran down Curling Luxury ridden by Castellano with De Sousa third aboard the favourite All You Know.
Going into the last leg de Sousa led on 22 points, Keane on 16 and Ho tied with Castellano on 12 thanks to two second place finishes.
De Sousa took the championship in emphatic style on John Moore's Experto Crede dashed through on the rail to hold the challenge of Ryan Moore on the John Size-trained Bank On Red.
With none of his nearest rivals scoring points in the last leg de Sousa finished well clear on 34 points with two wins and a second and third in the four legs.
Keane was runner-up on 16, while Ho shaded Castellano for third.A crowd of 30,174 attended the meeting with the betting turnover a massive HK$1.348 billion.