After missing a penalty kick in the 2001 Copa Mercosur final, his career with Flamengo was effectively over and he was loaned to Internacional and Mexican Primera División side Atlas in 2002 and 2003.

[5] Cassio's arrival at Adelaide United came after all of the club's options at left-back (Matthew Kemp, Adam van Dommele and Aaron Goulding) were either released or transferred at the end of the 2006–07 A-League season.

[6] Although failing to score during his debut A-League campaign, his 3 assists, and contribution of 14 shots on target, revealed how dangerous Cassio was as an attacking force.

[7] Despite a slow start to the 2008–2009 A-League season due to injury, Cassio proved just how valuable he had become to the club when he set up all three of Adelaide United's goals against FC Bunyodkor in the first leg semi-final of the 2008 AFC Champions League.

[8] On 15 October 2008 Cassio signed a new two-year deal with United despite interest from rival A-League clubs with the Brazilian stating that although they offered more money Adelaide was "like a second home" for the player.

In December, Cassio scored a brace in Adelaide's 6–1 demolishing of Wellington with both goals coming from unstoppable drives after he cut in from the left channel.