The 30-year-old has played as a right wing-back for the national side over the past three years following coach Ricki Herbert's move to a 3-4-3 system for the World Cup playoff against Bahrain. Now Bertos will slip a little further towards the back as he starts the upcoming A-League season at right-back for the Phoenix.
Manny Muscat filled the role last season but is moving back to his best position of central midfield this campaign meaning Herbert has turned to Bertos.
Initially Bertos thought it would be an interim measure, as others recovered from injury, but he's approaching it with the mindset it is where he will play the entire season. He's even hopeful of convincing Herbert he could do a job there for the All Whites if Herbert ever reverts to a back four.
It's a common scenario for strikers to slowly move towards defence as their pace departs but their reading of the game improves. Bertos has become more predictable in his attacking forays, often trying to beat players from a standing start, and recognises there are others who offer plenty in the front third at both the Phoenix and All Whites.
"The last few years I haven't scored many goals playing on the wing and that's one of the things wingers should be doing," he said. "We have brought in players who can do that so I thought, why not drop off a bit and become more of a defender?
"With the national team, there are a lot of younger boys coming through and a lot of them are attacking players - guys like Kosta Barbarouses and Marco Rojas - but there are not so many defenders. It's up to me to show I should own that position [of right-back] and prove I can do a job there.
"Ricki asked me [to play there for the Phoenix] during the off-season. I understand the reasons why because there's no one who can play that position at the moment. I thought I could fill in there but I have been doing alright and I'm actually really enjoying it.
"I like the fact you can attack from deeper, you have a lot more freedom and you get more time on the ball. It's taking a bit of getting used to but I am enjoying the change."
His attacking instincts means he's likely to venture forward often and it's something Herbert is encouraging. He wants the Phoenix to play a more attacking style this season as they look to achieve more than merely making the playoffs.
Bertos will have to balance that, however, with his core job of stopping opposition strikers, starting with Sydney's high-profile recruit Alessandro Del Piero when they meet in their season opener next weekend.
If he can pass that test, others will surely follow.
