Once a precocious young Socceroos wildcard himself, the City veteran believes his young teammate has the tools to bolt from the blue and make an unlikely run at a World Cup berth.
Younis, 20, has scored eight goals and notched three assists in 14 matches across the A-League Men and Asian Champions League since joining City on loan from Danish club Brondby in January.
In the process, the former Western Sydney teen sensation helped a flailing City seal a finals berth - and the reigning champions could finish as high as third if they beat Adelaide at AAMI Park on Sunday.
"He's been really important for the team. We went through a phase of not being able to score too many goals and he's come in and done that," Leckie told AAP.
"He's still very young, but he backs his ability, he's a strong and powerful player.
"He's got certain weapons - he's still quite raw because he's young and I remember that was sort of the picture that I had when I was younger. I played very direct with speed and power.
"And I think when you have weapons where you can make something happen from nothing, you can just have one moment to create a goal or assist - it goes a long way.
"He's definitely in a great position at his age."
Leckie was confident Younis would be able to sharpen up the rest of his game in time and noted the winger, whose father Ray Younis is Western Sydney's strength and conditioning boss, already had a good mental and physical base.
Leckie was first selected for the Socceroos as a 21-year-old and attended the 2014 World Cup at 23.
When asked if Younis was the type of player that could offer something if picked for the World Cup, Leckie said: "Yeah, for sure.
"Some games he's firing all game, and then there's others where you think he's been quiet and it hasn't gone too well for him but he still gets a goal or assist.
"A young player like that is someone that you could potentially consider to come as maybe a game changer, or someone that can just make something happen in the latter stages of the game.
"Of course the coaching staff of the national team have their ideas of what type of players they want and how they want to go about the game.
"But if he's any chance, he's definitely put himself in a position to at least get the question asked, because his numbers since he's been back are really, really good."
Leckie himself is back playing after returning from hip surgery that City hope will end his own cursed run of soft-tissue injuries.
The 35-year-old, one of Australia's heroes in Qatar who also played at the 2018 and 2022 World Cups, is yet to feature under Tony Popovic due to his poorly timed injury setbacks.
Now building minutes, Leckie is refusing to look too far ahead, citing his lack of consistent game time over the past two years and trying to stay fit and enjoy his football.
"I said before I'd even returned that it was silly to even think about it," he said.
"Because first and foremost I need to get myself into a situation where I'm playing games, not just 20 minutes off the bench.
"If there's any hope anyway it comes down to how I'm playing - and there's not really an option to even consider if I'm not playing.
"So I'm not really focused too much on it. Obviously, I know at the end of the season it's there but I'm just trying to take it a day or a week at a time, a game at a time, to build myself up to even give myself a chance."
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