It is a phrase that would strike fear into any opponent, no matter who you are. A few months ago Javi Martínez offered this unassuming yet terrifying description of himself. "I'd say I am the most German of all Spanish footballers," he said, conjuring images of an über-player, a technical beast capable of both tiki-taka passing as well as German discipline and endeavour. No wonder Bayern Munich paid Athletic Bilbao a record €40m (£34.2m) for him last summer.

Barcelona, who face Bayern and Martínez at the Allianz Arena on Tuesday night, and Real Madrid were interested, as were, reportedly, Manchester United but Bayern were desperate to get their man. The club president, Uli Hoeness, admits they probably paid €10m (£8.5m) too much for Martínez – "It is a lot of money for a water carrier," he said – but they felt he was exactly the type of player lacking when they lost the Champions League final against Chelsea last May.

Martínez has been described as a modern-day Stefan Effenberg, which is no bad thing in Bavaria. The former Germany midfielder, a wonderfully talented footballer with a fondness for an altercation (just ask Berti Vogts), won the Champions League in 2001 and three Bundesliga titles during two stints at the club. Now Martínez has been asked to deliver Bayern's fifth European Cup, just as "Effe" led the club to their fourth two years after that traumatic defeat by Manchester United at Camp Nou.

And Martínez, a 24-year-old Basque, is more than happy to be compared with the man known as "Der Tiger" to his team-mates. "My task is to create a balance for the team," Martínez told the Süddeutsche Zeitung. "I am, so to speak, here to help other players. I should make sure that there is equilibrium between attack and defence. I have heard the comparisons to Effenberg and he was certainly a player who covered a lot of kilometres. Xavi and [Andrés] Iniesta are definitely not like that. [Sergio] Busquets a little bit more but it could well be that I am, from the current Spanish internationals, the player who resembles Effenberg the most. You could say that I am the most German of all Spanish footballers."

Martínez is not the most stereotypical of Spanish footballers. He is unusually tall (among the current international crop), at 6ft 3in, and there is a hardness to him not always noticed in his Spain team-mates. In 201 games for Athletic he was shown 58 yellow cards and was sent off five times. This is a man who does not shirk a challenge.

There is a brilliant picture from the Under-21 European Championship in 2009 when Mesut Ozil is trying some fancy-dan tricks in the middle of the pitch, completely unaware that Martínez is flying in two-footed from the left, with his studs seemingly aiming for the Germany playmaker's ankles. Pretty? No. Effective? Yes.

On Tuesday night against Barcelona (so the Bayern plan goes, at least), he will be a giant pillar of strength amid an ocean of Catalan twinkle toes. Not that Martínez will have to do all the hard work himself. The Spaniard has been effusive in his praise of his partner in defensive midfield, Bastian Schweinsteiger, saying after the recent game against Wolfsburg that the Germany international is "a bull" and "a force of nature".

Schweinsteiger has returned the praise, saying "Javi is such an intelligent player, he does so many things right".

It has not been all straightforward for Martínez during his first season in Germany. He had a ludicrously short break last summer, playing at both Euro 2012 and the London Olympics after a gruelling season with Athletic in which they reached the Europa League final, and he struggled with minor injuries for the first six months at Bayern. Last month he was even dropped from the Spain squad but there is no doubt in the player's mind that he made the right decision in moving to Munich last summer.

Martínez is learning German with a passion and has, perhaps more worryingly, recently declared his love for German music in general and the rapper Sido in particular. He has five 90-minute German lessons a week and has recently taken it upon himself to "study" TV footage of his team-mates' post-match press conferences. Only a very committed man would do such a thing.

But the hardcore language training seems to have paid off. Martínez says there is now only one man he now struggles to understand, the assistant coach Hermann "Tiger" Gerland. "But that is probably not a disaster," he says. "Even the German players can't understand him." Martínez claims he now grasps 60-70% of "football-German" and that he speaks to Schweinsteiger in "a bit of German, a bit of Bayrisch and quite a bit of English".

But while the language has been easy to pick up there are still some aspects of life in Munich that the Spaniard finds somewhat baffling. "People are so honest here," he told the Munich paper tz recently. "Take the newspaper vending machines. They trust people to put money in [despite the fact that they are unlocked]. I can't believe that. That would never work in Spain. Also, another thing, the overall volume here in Munich is much lower than what I am used to. Recently I was out with a few friends in town and it felt as if we were being the noisiest people in the world. People here are much quieter and much more respectful."

And respect is something Martínez learned about early in his life, recalling once how his mother used to chase him around the house with anything she could grab – a frying pan or, er, slippers. And what had Martínez done to incur her wrath? Not much: destroyed a flower pot with a football, set fire to the bed linen or put his brother's schoolbooks in the kitchen sink – and then turned on the tap.

He is an intriguing man, Javi Martínez, and a very good footballer. Barcelona already know this but that does not mean they know how to stop him.