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 certainly 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, tells Sky Sports.
"He has four characteristics which are not easy to bring together. He is a very humble and simple person, but he is also very proud and has a really strong personality. You don't often find players with all those qualities together. Martin is one."
Benoit Cachenaut, a centre-back who played with a teenage Zubimendi in Real Sociedad's C team, uses the same word to sum him up. "He was always a very complete player," he says to Sky Sports. "Technical, quick, intelligent, potent.
"You could already see he had everything to get to the highest level. But as well as being very good on the pitch, he was a very humble guy, always smiling, always very friendly."
Cachenaut recalls a visit from Zubimendi while holed up in hospital after having knee surgery. "He was one of the only team-mates who came to see me," he says. It was typical of a player known for going the extra mile on the pitch as well as off it."
"He was a very disciplined guy who was very serious about his work," adds Zulaika. "He was smart, he listened to his coaches, and he was polite and respectful with everybody."
He made a similar impression on Carlos Martinez, a former right-back with more than 200 appearances for Real Sociedad.
"As soon as we all saw him play, we could see he had something different, something that catches the attention of those of us who have played football," he tells Sky Sports. "It's just the way he moves the ball and the personality he showed even at such a young age.
An exemplary professional, Zubimendi went on to make more than 200 senior appearances for Real Sociedad. His personality now forms a significant part of his appeal to Arsenal.
The club need a player with his profile in the No 6 role. "They still haven't got a deep midfielder who can take the ball on the back foot," said Sky Sports pundit Gary Neville recently.
But they also need someone to replace the experience and leadership they will lose with the imminent departure of Jorginho. Zubimendi, although seven years younger, fits the bill having led by example throughout his time at Real Sociedad.
Crucially, he is also a good fit for Arsenal's manager, with whom he shares common ground. Mikel Arteta, like Zubimendi, grew up in the city of San Sebastian and played for Real Sociedad. They even started out at the same youth club called Antiguoko.
'More like Alonso than Arteta'
Arteta was viewed as a future star right from the start of his time with Antiguoko and went on to join Barcelona's La Masia academy aged 15. Zubimendi, though, did not initially stand out.
"He was very shy and hadn't developed much physically," Roberto Montiel, the club's long-serving vice-president, who coached a young Arteta, recalls to Sky Sports.
"Real Sociedad had him on trial a couple of times but didn't sign him," he adds. "He wasn't deemed to be at the right level. It was only when he was 14, after we told them Atletico Madrid were also interested, that they decided to take him."
By that point, Zubimendi was more developed physically and better able to express his talent.
"He could play with both feet, he was a quick-thinker, and he was always in the right positions on the pitch," says Montiel. "He was like Xabi Alonso in the way he saw football."
And Montiel should know. He coached Alonso in the same youth team as Arteta. Alonso would go on to coach Zubimendi in Real Sociedad's B team. The Antiguoko connection continues as, five years on, Zubimendi prepares to work with Arteta at Arsenal.
"I would say Martin was more similar to Xabi than Mikel, as a boy as well as a player," says Montiel.
"Like Xabi, he was a great passer who made good decisions. He won the ball well and knew how to protect it. But he was also a bit of an introvert, similarly to Xabi, whereas Mikel was all-in. Martin could go a bit unnoticed because of that."
It all changed in Real Sociedad's academy, where Zubimendi grew in confidence as well as physical stature. "He was already a very good player for them in his first year but it was in his second, as an U16, that he really exploded," recalls Montiel.
"It was pretty clear to everyone at the club that he was going to make it to the first team," adds Zulaika. "The qualities he showed then were similar to the ones you see now. He is so good with the ball, controlling the game, passing.
"But he defends brilliantly as well. He is good in all aspects. He can pass short or long, he can break lines by driving forward with the ball, he gets shots off, he runs a lot of kilometres, he cuts out so many passes on the ground and in the air.
"When he made the step up to join us in Real Sociedad B, he was a young player playing with guys who were three or four years older than him but it didn't faze him at all.
"He wasn't much of a talker but that was understandable given he was mixing with more senior players. He did his talking with the ball. It didn't take him long to win his place in the team. Once he had it, nobody could get it off him."
Zubimendi went on to become similarly important at first-team level, playing more minutes for Real Sociedad than any other outfield player across the last three seasons.
But the best demonstration of his ability to excel under pressure came on the international stage last year, when he stepped in seamlessly for the injured Rodri at half-time of Spain's European Championship final win over England in Germany.
Martinez puffs out his cheeks at the mention of it. "You saw how willing he was to take the ball, to drive forward, to be brave. He just has so much confidence in his ability."
"The only reason he wasn't starting was because he was behind the best player in the world in his position," adds Zulaika. "We were all well aware of his immense quality but you need to do it on the biggest stage and that is what he did against England."
'He could play for any team in the world'
Zubimendi showed off his full repertoire in that second half in Berlin, snapping into challenges, zipping passes through the lines and driving Spain forward in a manner that is typical of him.
They are qualities that Arsenal will now aim to harness. Zubimendi excels at circulating possession and constructing attacks from the base of midfield, much like Thomas Partey and Jorginho, but he is also a brave and forward-thinking passer.
"It was brilliant playing behind him as a central defender because he always asked for the ball and he was never afraid to play," says his former team-mate Cachenaut.
It can be seen in the numbers. This season, Zubimendi has sent a higher percentage of passes forward than either Partey, Jorginho or Declan Rice, at 31.49 per cent. His completion rate is lower, at 84.23 per cent, but only because he takes more risks.
Of midfielders in LaLiga this season, only four, all of whom play for either Barcelona, Real Madrid or Atletico Madrid, in Pedri, Federico Valverde, Rodrigo De Paul and Jude Bellingham, have made more progressive passes than Zubimendi.
That level of incision will be valuable to Arsenal, particularly after a Premier League season in which they struggled to break down deep-lying defences on a regular basis.
"I think he is a profile of player they lack," says Montiel.
"They have Declan Rice, they have Mikel Merino, they have Martin Odegaard, but they are missing something when playing out from the back with one or two touches.
"I think Zubimendi is the kind of player they need for that. He can play all kinds of passes and on top of that he reads the game so well. I think he could be a really good signing for them."
"Without doubt," agrees Zulaika. "Whatever the competition, whether it's the Premier League, LaLiga, or the European Championship, he would have a place in any team in the world.
"I can't see many better players in his position."
"He reminds me a lot of Alonso, who had great success in the Premier League, and he is also very, very good tactically," adds Martinez. "He can drop in and cover at centre-back, at full-back. He understands the game so well. I don't think he will have any problems at all. If you ask me, he is ready."