Scotland carries a narrow but crucial 1-0 advantage heading into Sunday's second leg against Greece at Hampden Park, but a new threat has emerged that could potentially derail their plans: 17-year-old Konstantinos Karetsas, who made an impactful debut for Greece in the first leg.
The teenage sensation was introduced at half-time in Athens and immediately transformed Greece's performance, helping shift momentum in the home side's favor. While Scotland managed to preserve their lead, Karetsas came tantalizingly close to changing the outcome – his curling effort missed the crossbar by inches, and his perfectly weighted cross led to Christos Tzolis hitting the post.
Born to Greek parents in Belgium, Karetsas has spent his entire life in Genk, where he quickly rose through the academy ranks to make his first-team debut last season as a 16-year-old. This season, he has established himself as a regular, starting 14 games and appearing as a substitute in 11 more, primarily as an attacking midfielder for Jupiler Pro League leaders Genk.
Despite representing Belgium at youth level as recently as November, Karetsas chose to commit his international future to Greece. As Greek journalist Stephen Kountourou explained on BBC Scotland's Daily Football Podcast: "We had to fight tooth and nail with the Belgian FA to stop him representing them and that was seen as a big coup for Greek football, because Karetsas is rated not just as a potentially decent talented player but as one of the big players for the future in international football."
For Karetsas, whose idols include Neymar and Ronaldinho, the decision was driven by emotion. "My heart beats only for Greece - my homeland fulfils me completely," he was quoted as saying.
His performance in Athens was so impressive that BBC Scotland's co-commentator James McFadden expects him to start at Hampden: "I thought he looked really classy, composed, willing to take people on and, when he came on, he was their main outlet. They were just desperate to get the ball to him, so I think he comes straight into the team."
Pat Nevin, working at the game for BBC Radio Scotland and Five Live, shared similar sentiments: "I thought he made a huge difference, probably the main reason the game changed massively in the second half." Nevin added that Scotland manager Steve Clarke acknowledged after the match that the youngster is "pretty special and somebody that needs to be kept a really close eye on."
Karetsas himself appears unfazed by the occasion. "Already, I feel like I belong in the national team. I'm really happy I made the decision to be here," he said after the match. "I was up against Andy Robertson. He is a very good player, but when I go one on one, I don't see who's in front of me."
Despite the defeat, the teenager remains confident about the second leg: "We lost, but we played well in the second half and that is how we have to play on Sunday in Scotland. I think, if we play like that, we will win."
Scotland goalkeeper Craig Gordon acknowledged the threat posed by Karetsas: "He looked fantastic when he came on. He's someone we'll need to look out for in the second leg. I haven't seen many debuts like that from someone so young. It was an impressive first cap for him, but thankfully we managed to keep him out."
As for tactical adjustments to counter the Greek wonderkid, McFadden doesn't expect Clarke to make significant changes: "I think you respect the fact he's a very good player, but it's Andy Robertson that's going to be playing against him. I think if you said to him, 'I'm going to get someone to help you with this young player', I don't think he'd be too happy."
Nevin offered a more nuanced view: "I think he'll consider it, because if you don't consider it and he has a great game, you've made a mistake. I think it's more, don't change your entire attitude but be very aware, if it starts being a problem, you can adapt to it."
As Scotland defends their slender advantage at Hampden, containing the talented Karetsas may prove crucial to their hopes of advancing.
