D'Souza was captain of the Indian team in the 2005 Junior Hockey World Cup. The same year he was part of the junior team in the 6 nation invitational tournament in Kuala Lumpur, Malaysia. 2006 was a busy year for the Indian team with major tournaments lined up and the selectors expected Adrian to play a pivotal role in the team. The year saw him represent the team in the Sultan Azlan Shah tournament (Malaysia) in June, the Champions Trophy (Spain) in July, the World Cup (Germany) in September, and ending with the Asian Games (Qatar) in December, while missing the Commonwealth Games in Australia due to an injury. In 2007, he was part of the bronze-winning team in the Champions Challenge in Belgium and the gold winning team at the Asia Cup. Due to a hamstring injury, Adrian had to pull out from the 2008 Olympic Qualifier camp. India could not beat Great Britain in the final and missed the Olympics for the first time in 80 years. Adrian, along with his parents, watched the game in Mumbai. He was back after a break of 2 months and was selected for the 2 legged 4 Nation tournament in Perth and Darwin. The tournament also included hosts Australia, China and South Korea. Adrian performed relatively well in the 2008 Sultan Azlan Shah Cup, having played a great game against Malaysia in the semi-finals. India scored from a penalty corner and Malaysia could not prevent India from making it to the final of the Sultan Azlan Shah after 13 long years. Facing a tightly contested match against Argentina in the finals, India lost in the extra time. Adrian played his last international tournament, the Sultan Azlan Shah Cup in 2012.