The ferocious competitor, who excelled alongside Mark Bresciano, Jason Culina and Tim Cahill in an Australian midfield brimming with ability at Germany 2006, is convinced that Postecoglou's new crew offer the national team more depth than Hiddink's halcyon days.
Postecoglou has assembled up to nine midfielders Grella considers more than worthy of the green and gold with Aaron Mooy, Tom Rogic, Massimo Luongo, Mile Jedinak, Mark Milligan and Jackson Irvine at the top of the pyramid, and the likes of Terry Antonis, Burnley teenager Aiden O'Neill, Aston Villa's Jordan Lyden, Denmark-based Mustafa Amini and Roda's Danny De Silva all waiting for the chance to join Ange's ensemble.
“There is more depth now than in my era … we were a small group performing at club level in good leagues and maybe we stifled opportunities for other boys to get opportunities," said Grella, who played 46 times for his country.
“That isn’t the case under Ange who has a lot of good options in midfield, whereas in my day the numbers were more limited.
"He has players who are both technical and also modern day midfield players full of energy and tactically aware.
"They would give us a run for out money for sure … when I was in the national team we had two number 6's, then your floating players like Bresh and Timmy Cahill in more advanced areas.
"Right now, you probably have three players in number 8 roles, Mooy, Rogic and Luongo and even Millsy to a certain extent. There’s a different profile of player with different characteristics.
"When you look at young players coming through, like a Danny De Silva, you have to be encouraged. When I watch the Australian team, I like what I see."
Postecoglou's current crop again showed their qualities as Australia bolted from the starting blocks in the final dash to Russia with wins over Iraq and UAE, and are in pole position ahead of next month’s qualifiers at home to Japan and in Saudi Arabia.
Grella sees qualities across the board, adding: “Tommy Rogic is an exciting player, very creative but even Aaron Mooy, a different style of creativeness, but also very clever in what he does and also very good with his deliveries.
"Add Jackson Irvine to those who are already there and Ange has eight or nine good midfielders to pick from."
Grella is reticent to be too glowing in his assessment of Irvine, providing the disclaimer that he manages the player.
“I represent him and you can be seen as biased but the facts are that has had a fantastic start to the season in the Championship with Burton Albion and is playing like he's been there 10 years which has a lot to do with the mentality and the style of management of Nigel Clough."
Looking further ahead, Grella sees 19 year old Perth Glory product De Silva as a diamond in the making.
"We are going to see his true colours this year," he said. "He’s had fantastic pre-season ... I watched him play a month ago. He came on in the Dutch first division and changed the game, which is easier said than done.
"Danny has an unbelievable future and he has already done 12 months in Europe."
Grella feels that Postecoglou should be credited as the architect of Australia’s renaissance.
"He has brought a new mentality, and has restored the pride of the national team and everybody is fighting for a position in the squad," he said.
"He isn’t scared to bring in fresh faces ... some people had question marks when he was appointed but he’s proved to be fantastic in his job and has brought new energy to the team."