Arsenal believe they are acquiring one of the world's best holding midfielders in Martin Zubimendi and they are not the only ones. Having also been coveted by Liverpool, Manchester City, Real Madrid and Barcelona, his elite credentials are clear.

Zubimendi won the European Championship with Spain last year and has thrived domestically as well as internationally, helping boyhood club Real Sociedad win silverware in the Copa del Rey and playing a key role in their return to the Champions League last year.

There is a lot to like about him. The 26-year-old excels in and out of possession, marrying intelligence and outstanding technique with deceptive physicality at the base of midfield, where he acts as a passing metronome and a screen for his defence.

But that is not all. The impression left by speaking to his former coaches and team-mates is of a player defined by his strength of character as much as his technical and physical attributes.

"The first thing to say about Martin is that he is a complete person as well as being a complete player," Aitor Zulaika, a former Real Sociedad coach who worked closely with Zubimendi as assistant to Xabi Alonso in the club's B team,...