The most capped Australian has called time on his Socceroos career less than eight months out from the 2014 World Cup in a move that has certainly stunned former teammate Cahill.
"It's incredible. I feel it's a massive surprise from someone that I've looked up to my whole career," Cahill told AAP.
"He's one of the greatest ambassadors to ever play the game, but most importantly a true gentlemen on and off the park.
"It's a truly shocking night here in New York for me."
The former Everton star added: "He's called it a day and players make up their own mind. Whether it's the right time, no-one knows.
"But the best thing is he's all class, the way he's done it is exceptional.
"I feel Schwarzer's seen the talent and he's probably thought, 'You know what, the kids are ready' and he stepped aside.
"It shows the true mark of a man that he can do what he's done today, hang up his boots or gloves from playing internationally."
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