When Metcalfe scored against Turkey in Australia's opening group match, his ecstatic, knee-sliding celebration almost appeared cathartic.
Between injury and being overlooked by his former coach Alexander Blessin, Metcalfe received just 576 league minutes and made only three starts for St. Pauli across 25 Bundesliga appearances last season.
But Socceroos coach Tony Popovic has always kept the faith and is benefiting from Metcalfe, 26, enjoying his football and making every moment count at his first World Cup.
"It's been nice, it's the biggest stage in the world," Metcalfe said.
"It has been sort of a release of the build-up that I've been feeling in the season - being able to let it out on the pitch and enjoy the moment and not really being nervous and just get on with it.
"I think it's really helped me, to be honest.
"Because there's a lot of inner anger from the season, so it's probably benefiting me."
With St. Pauli relegated to the 2.Bundesliga and a new coach, Marcel Rapp, Metcalfe, contracted through 2027, could have a bigger role there.
He is already receiving interest elsewhere, given his World Cup, but is focused firmly on Australia's round-of-32 clash with Egypt on Friday (Saturday AEST).
"I'm not really thinking that far ahead, to be honest," Metcalfe said.
"I just really want to continue playing the way I've been playing.
"Whatever comes from it, I'm excited. But I'm looking forward to this next game. That's it."
Metcalfe has often been used as the left-sided attacking midfielder, or inverted winger, under Tony Popovic and has a good understanding with Nestory Irankunda and Mohamed Toure.
"I'm not the most flair-y sort of creative player up top, and I know that," he said.
"I'm lucky to have two other boys next to me who can do that stuff. I sort of see myself as the first line of defence.
"I'm pretty aware of what I have to do tactically and defensively, and I think that helps the players behind me position themselves better."
Popovic has rotated his attack and Metcalfe started against Turkey, was used off the bench against the United States then started against Paraguay.
"Everyone wants to play," he said.
"But at the end of the day, everyone's here for one reason, and if I'm not playing, then for me it doesn't matter, just as long as we win
"If everyone has that exact same mentality, I think it's quite difficult to beat.
"Because when everyone's on the same page and everyone's willing to work for each other, then it's not just individuals, it's a very strong team."
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