Scotland head into Sunday's second leg at Hampden Park with a hard-fought 1-0 advantage, but no one in Steve Clarke's squad is underestimating the challenge that still lies ahead.
Greece's performance in the second half of the first leg in Athens was transformed by the introduction of 17-year-old Konstantinos Karetsas.
The teenager, who plays for Genk in Belgium, made his international debut under manager Ivan Jovanovic and quickly shifted the momentum in favor of the hosts.
Karetsas came close to finding an equalizer, narrowly missing the target with a curling effort and delivering a tantalizing cross that Christos Tzolis headed against the post.
Despite his best efforts, Scotland managed to hold on to their slender lead.
Born and raised in Belgium to Greek parents, Karetsas has emerged as a key player for Genk this season, featuring regularly in the Jupiler Pro League.
Though he represented Belgium at youth level, Greece won the battle to secure his allegiance for international football.
Greek journalist Stephen Kountourou, speaking on BBC Scotland's Daily Football Podcast, described the recruitment of Karetsas as a significant victory for Greek football.
"We had to fight tooth and nail with the Belgian FA to stop him representing them," Kountourou explained.
"He's seen as one of the big players for the future in international football."
Karetsas, whose football idols include Neymar and Ronaldinho, has no regrets about his choice.
"My heart beats only for Greece—my homeland fulfils me completely," he said.
His impressive debut left a mark on BBC Scotland's co-commentator James McFadden, who expects the teenager to start at Hampden.
"He looked really classy, composed, and willing to take people on."
"When he came on, he was their main outlet," McFadden observed.
Pat Nevin, covering the game for BBC Radio Scotland, shared similar praise:"He made a huge difference."
"The game changed massively when he came on. Even Steve Clarke acknowledged that he's a special talent."
Karetsas, brimming with confidence, is eager for the second leg and relishes the challenge of facing Liverpool and Scotland captain Andy Robertson again.
"I feel like I belong in the national team already," Karetsas said.
"I was up against Andy Robertson—he's a very good player, but when I go one-on-one, I don't see who's in front of me."
Scotland goalkeeper Craig Gordon admitted that Karetsas posed a real threat:"He looked fantastic when he came on. We'll need to be mindful of him at Hampden, but hopefully, we can keep him quiet again."
While some believe Scotland may need to adjust to contain Karetsas, McFadden thinks Robertson will be ready for the challenge.
"I think if you suggested to Andy Robertson that he needs extra help to handle a teenager, he wouldn't be too happy," McFadden joked.
With Hampden Park set for a thrilling second leg, all eyes will be on whether Karetsas can replicate his impactful debut or if Scotland can secure their place with a disciplined defensive display.