Riding his stallion Mumbai, Kukuk clocked an impressive 42.68sec to beat two-time GCT winner Ben Maher, who was on Faltic HB.

Maher finished in 43.50 to take silver, while Paris GCT Grand Prix winner Marlon Zanotelli of Brazil and Like a Diamond van het Schaeck claimed bronze in 43.62.

Sweden's Henrik Von Eckermann and Iliana finished fourth on 44.20 while Pieter Devos, riding Mom's Toupie De La Roque, completed the top five by finishing in 44.82.

"It means everything to me," Kukuk said after the win.

"I have put enormous effort into this sport and all the horses, especially Mumbai over the last 10 years, since I started at Ludger’s and I always dream about winning one of these Global Champions Tour Grand Prix.

"I am so so happy in this moment, I really can not believe it.

"I can’t find the words and I am also a little bit shaky, but it’s just amazing.

"I just realised that the breeder of Mumbai is here and it is her birthday - I mean I think the day was just made for us."

The Rome event has intensified the battle in the overall standings, with German Christian Ahlmann having only a six-point lead at the top with 238 points.

Maher’s silver helped him close the gap to Ahlmann and Belgium's Devos, with 221 points, is also in contention at the top with two more rounds in New York and the final in Riyadh.