It is the day before the start of Euro 2012 and at Greece's tournament base in Jachranka, a village north of Warsaw, the national team manager, Fernando Santos, is telling his players who will be starting the next day's opening match against co-hosts Poland. Suddenly, a hulking 20-year-old loses his temper, his cheeks turning red with rage as he hears he is not in the side. Unable to calm down he tells Santos that Greece will lose without him, leaving the Portuguese, as well as the more experienced members of his squad, looking on in disbelief. Some start laughing, only to be confronted by a fierce stare from the angry young man.

Of all the stories that have been told about Kyriakos Papadopoulos since he made his debut for Olympiakos aged 15, and more recently following reports linking him with a move to Liverpool, perhaps this is the most telling of a defender who is becoming renowned across Europe as much for his confidence and combustible personality as for his talents on the pitch. At Schalke, Papadopoulos's current club, the supporters describe him as "verrückt" – crazy – while acknowledging that three years after arriving at the Veltins-Arena, he has become a star of the team.

"He is a huge talent," says Philipp Selldorf, Schalke correspondent for Süddeutsche Zeitung. "Papa was only 18 when he came to Schalke but he got into the team very quickly and has done well ever since. The supporters also love Papa because of his passion. They can see that he is always fighting for the ball, always trying to win possession. They admire his bravery but also worry that he might be a little mad. This is something the management also worry about – if Schalke are losing at half-time they find it hard to get through to Papa in the dressing room. He just sits there looking frustrated and down, and that has sometimes affected his decision making; made his tackling more wild. But in fairness, Papa has not been sent off many times for Schalke."

Twice in the last couple of seasons to be precise, although it could well have happened more during the most recent campaign had a knee operation not restricted Papadopoulos to 16 appearances in all competitions. It is also worth noting that across the last two Bundesliga seasons, the 21-year-old committed 2.13 fouls-per-game, significantly more than many of the division's other leading centre-backs, such as Dante (1.34), Manuel Friedrich (1.03), Neven Subotic (0.92) and Mats Hummels (0.70)

But Opta's statistics from the same period also highlight Papadopoulos's positive influence on Schalke and why Liverpool appear so keen to sign him. In comparison with the aforementioned centre-backs, he has scored the joint-highest number of goals (3), has the second-highest tackle-success rate (84.83%), made the most clearances-per-game (6.51) and the most interceptions-per-game (3.77), with only his passing figures letting him down.

"He definitely needs to work on his passing," says Stavros Drakoularakos, a writer with Sport 24, Greece's largest sport website. "He is quick, strong and comfortable with the ball, so if he can improve his distribution skills then Papadopoulos really can go to that next level and become one of the best defenders in Europe."

In Greece they have known about Papadopoulos ever since Olympiakos brought him to their youth academy from Svoronos Katerinis, his hometown club, in July 2007. A story soon appeared on the front of FOS, the country's biggest-selling sports newspaper, declaring the club had just signed the nation's next star and on 2 December that year, in a match against Atromitos, Papadopoulos came off the bench to become the youngest player to compete in Greece's Super League. He was 15 years and 283 days old.

Papadopoulos soon became a fixture in the Olympiakos side, as well as impressing at Under-17, Under-18 and Under-21 level for Greece, with his combination of pace and power, allied to a robust frame and superb aerial ability for someone who is barely 6ft — "watching him challenge for every high ball makes you think he's a colossus whereas actually he's not that tall for a central defender," says Selldorf — alerting the attention of scouts across Europe. In June 2010 he joined Schalke and departed from his homeland with a message that screamed with confidence and ambition.

"When Papadopoulos announced he was going to Germany he described Olympiakos as having been a 'stepping stone' in his career," says Drakoularakos. "For 99% of Greek players Olympiakos is not a stepping stone, it is the pinnacle. So this comment came as a shock and people started accusing Papadopoulos of having a big ego."

Many of Papadopoulos's Greece team-mates are likely to have thought the same after his fit of pique prior to the Poland game last summer. The defender arrived at Euro 2012 having made his international debut 12 months earlier in a qualifier against Malta, and while he impressed in that match, scoring one of Greece's goals in a 3-1 victory, and then started four of the team's final five qualifying matches, he remained behind Avraam Papadopoulos and Sokratis Papastathopoulos in Greece's centre-back pecking order. It was a surprise only to Papa that Santos did not include him in the side who faced the Poles.

The defender stewed among the substitutes at Warsaw's National Stadium but he did not have to wait long for his moment, coming on in the 36th minute for Avraam Papadopoulos after he had suffered a knee injury. The youngster impressed in the 1-1 draw and again during the 2-1 defeat to Czech Republic. But it was his performance in Greece's final group match, the 1-0 victory over Russia, that really caught the eye, and from there he firmly established himself in the national team.

"Papadopoulos was fantastic against Russia, the man of the match," says Drakoularakos. "It was a big moment for him and also the moment when the rest of the squad truly recognised his talents. Greece still has many members of the side who won Euro 2004 and because of that achievement they do not readily compliment younger players when they are selected for the national team. But the senior guys are all happy to talk about Papadopoulos – they recognise he will soon be their most important player. My view is that he will be Greece's captain in the next five or six years, although if you asked Papadopoulos he would probably tell you he is ready to be captain now."

Having all but recovered from his knee operation, the next challenge awaiting Papadopoulos appears to be filling the void left at Anfield by the retired Jamie Carragher. Brendan Rodgers has identified him as the new leader of Liverpool's backline, with his pace allowing Rodgers to implement the high-line defence that he has been unable to establish. Being right footed, Papadopoulos would also compliment the left-footed Daniel Agger.

Papadopoulos's agent, Paul Koutsoliakos, has said the player is happy to see out the remaining three years of his contract at Schalke, particularly given they have qualified for next season's Champions League.

But privately Papadopoulos has his heart set on a switch to Liverpool, so much so that he travelled to London last month to watch their 3-1 victory at Fulham. While there, Papadopoulos also spoke to Greece team-mate and Fulham midfielder Giorgos Karagounis about life in the Premier League.

For their part, Schalke have said they have no desire to sell Papadopoulos, but with a plan in place to clear debts of over £15.4m club officials are open to selling him for the right price. Indeed, Schalke appear to have already begun preparing for life without the centre-back having signed Felipe Santana from Borussia Dortmund.

Liverpool fans generally appear excited about the pursuit of Papadopoulos, with some taking particular delight from a YouTube clip showing the player's reaction to being grabbed around the throat by Greece team-mate Georgios Samaras. Having released himself from Samaras's grasp, Papadopoulos glares at the striker with a look of almost murderous intent, his eyes bulging, those cheeks reddening with anger once again. Verrückt, as they say in Gelsenkirchen, and now possibly heading this way...