For the 2007–08 season Adelaide recruited ex-Socceroo Paul Agostino "marquee", Ivorian Jonas Salley and ex-Olyroo Kristian Sarkies.

One of the success stories of the season was the signing of former Flamengo FC player Cássio on a free transfer from Brazilian club.

Shaun Ontong and Matthew Mullen from the AIS, were also signed to replenish their defensive stocks after the departure of Kristian Rees, Adam van Dommele and Aaron Goulding.

Adelaide United participated in the 2008 AFC Champions League after finishing runner-up in the 2006–07 regular season and finals series to Melbourne Victory.

In Changchun, Adelaide withstood considerable pressure to achieve an historic 0–0 draw, thus becoming the first Australian team to ever progress to the knockout stage of the Asian Champions League.

Adelaide drew J-League and Emperor's Cup champions Kashima Antlers in a two legged quarter-final starting in Japan, where they managed a 1–1 draw.