The 27-year-old defender has played in the A-League since 2006, first with Sydney FC and Perth Glory then three campaigns with Newcastle Jets.
However his game has gone to a new level since he linked with former Socceroos defender Popovic at league newcomer Western Sydney Wanderers this season, playing alongside skipper Michael Beauchamp in one of the strongest backlines in the league.
A trimmed down Topor-Stanley feels it's no coincidence he's found his best form under the guidance of Popovic, who used to play in the same left centreback position he occupies.
"Coming under a new coach like Popa, it's had a massive influence on me," said Topor-Stanley on Tuesday.
"Not just in my football but how to treat my body and to be the ultimate professional.
"Obviously it's an advantage that he knows exactly what to do in my position. He's been there and done that so his knowledge has been invaluable for me."
Popovic said Topor-Stanley deserved most credit, given the hard work he'd done to raise his game.
"It would probably help that I played there and I can pick up on little details that might help his game," Popovic said.
"But it's Nikolai who goes out there every week and trains the way he does and plays the way he does.
It's been four years since Topor-Stanley received his only two national team caps, both in 2009 under then coach Pim Verbeek.
"We're very happy with his form here but it's up to the Socceroos and Holger Osieck to assess (if he's good enough for a call-up)," said Popovic.
"But as a left centre-back he's probably playing as good as anyone in the league at the moment."
Topor-Stanley said his sole focus was performing at club level but he acknowleged ambition to play for the Socceroos was still there.
"It is in the back of my mind," he said.
"I've had a very small taste of it and it was great, so to be back part of it again would be tremendous."