Barbarouses turned down a two-year contract extension with Wellington Phoenix in February 2010 for a three-year contract with A-League side Brisbane Roar. Brisbane Roar play an attractive brand of football and Barbarouses wanted the opportunity to play more regular football. In the 2009–10 season, which took the Phoenix into the finals, Barbarouses had had only three starts, and ten appearances off the bench.
Barbarouses made his debut for the Roar in Round 1 of the 2010–11 season, starting against Gold Coast United in a 0–0 draw on 8 August 2010. Barbarouses continued to start for the Brisbane team and played against his old club Wellington Phoenix, on 27 August 2010 at Suncorp Stadium. In the 73rd minute, he received a through-ball from team-mate Matt McKay and slotted home his first A-League goal for the Brisbane Roar. Barbarouses was named in the 2010–11 A-League All-Star Team after 12 goals in 33 appearances.
Barbarouses made his senior debut in a 2010 FIFA World Cup qualifier against Fiji on 19 November 2008. He trained with the national team before its World Cup qualifying play-off against Bahrain. Barbarouses attended a 12-day All Whites training camp in Auckland in April–May 2010 as a member of a 15-man squad of Australasian-based players. He was one of two forwards on the squad.
Barbarouses had stated that he would like to make the New Zealand 2010 FIFA World Cup squad. Although widely tipped to make the final 23-man squad travel to the 2010 FIFA World Cup, Barbarouses' name was missing when NZFA chairman Frank van Hattum read out the names at Auckland's Sky City on 10 May 2010. He was, however, named as one of seven non-travelling reserves.