During the 2007–08 season Bertos made fourteen appearances for the club and scored one goal and had two assists. On 24 January 2008, Bertos was signed on a free transfer by his hometown club Wellington Phoenix on a two-year contract. He made his club debut in the opening game of the 2008–09 season against Brisbane Roar. Bertos scored his first goal for Wellington against Sydney on 7 November 2008. He played in 16 of the 21 regular season matches making 14 starts with 2 goals and 4 assists. Bertos was named Wellington Phoenix Player of the Year for 2008–09. The 2009–10 season was incredibly successful for Bertos and the Phoenix. Bertos played a central role during the regular season to ensure a first finals appearance for the club. He played every game of the season, starting 23 of the 28 matches, scoring 2 goals and providing 8 assists. He holds the all-time leading assists record for the club with 12. On 1 October 2009 he signed a three-year contract extension. On 13 April 2014, the Phoenix announced he would be leaving the club. On 19 July 2014, he signed for Indian club East Bengal for a two-year contract. On the virtue of playing in 2010 FIFA World Cup, he qualifies as the marquee player of the club. He was issued the number 11 jersey. He made his debut in a CFL match against Techno Aryan on 23 August 2014, coming as a substitute for Mehtab Hussain. As the Indian Super League started, Bertos joined the competition by going on loan to NorthEast United. There he reunited with his former coach at national team Ricki Herbert. Bertos signed for Australian National Premier Leagues side Hamilton Olympic for the 2016 season after training for several weeks with Newcastle Jets. Bertos made his international debut against Iran on 13 October 2003 and has represented New Zealand over 50 times since. He has also represented New Zealand at under-23 level. Bertos is known for his dribbling and quality skills on the ball. This was shown in the New Zealand vs Brazil game in which he dribbled around two defenders to win a corner. He also played many one-twos and did a drag-back once in the second half. In the first game of the New Zealand vs Malaysia series (which New Zealand won 1–0), Bertos received the Man of the Match award for his magnificent dribbling performance and domination of the Malaysian defence. He represented New Zealand at the 2009 FIFA Confederations Cup in South Africa. He provided the assist for New Zealand's first two goals against World Champions Italy in a 3–4 friendly loss in Pretoria prior to the Confederations Cup.