Manchester United have confirmed the £56.7m signing of Ajax defender Lisandro Martinez on a five-year contract.
United have paid a guaranteed €57.37m (£48.3m) for the Argentina international, with an additional €10m (£8.4m) in add-ons agreed between the two clubs. The move sees Martinez link up again with former Ajax manager Erik ten Hag, who signed him for the club in 2019, at Old Trafford.
The 24-year-old has put pen to paper on a five-year contract in Manchester, with the option of a further 12 months, which would take him beyond his 30th birthday.
"It's an honour to join this great football club," Martinez said. "I've worked so hard to get to this moment and now that I'm here I'm going to push myself even further.
I've been lucky enough to be part of successful teams in my career and that's what I want to continue at Manchester United. There will be a lot of work to get to that moment, but I firmly believe that under this manager and coaches, and together with my new teammates, we can do it.
"I want to thank Ajax and their fans for all the support they gave me. I had an unbelievable time there but feel the moment is right to test myself in another environment. Now I am at the perfect club to do that."
Martinez arrived at United's Carrington training base on Tuesday alongside fellow new signing Christian Eriksen, who completed a free transfer earlier this month after his Brentford contract expired.
Arsenal were also interested in the Argentina international, but conceded defeat in their pursuit. While the Gunners' playing style, along with the prospect of playing for Mikel Arteta, appealed to Martinez, he has chosen to move to Old Trafford.
Around €2m (£1.7m) of Martinez's fee will be split between his old clubs, Newell's Old Boys and Defensa y Justicia, both based in Argentina, as part of the standard solidarity payments involved in international transfers.
John Murtough, United's Football Director, said of the club's new signing: "Lisandro is an outstanding player who will bring further quality and experience to Erik's squad.
"We are delighted that he has chosen to join Manchester United, and we are looking forward to seeing him develop further and help the team achieve the success we are aiming for."
Why did Man Utd want Martinez?
Sky Sports News senior reporter Melissa Reddy:
"United have needed a left-sided centre-back and the manager wanted somebody who's quite comfortable in possession.
"Under Ten Hag, United are going to have quite a proactive approach, build play from the back and he wanted to have a defender who is going to be an indirect threat at set pieces, confident and authoritative in the area.
He knows Martinez quite well and feels that he fits the bill. He's a defender comfortable defending in large spaces when the team pushes up.
"He is going to be okay to cover ground on his own but also he can bring the ball out and form parts of attacks which is what Ten Hag wants. He feels this is money well spent for United."
Last season, Martinez averaged more passes per 90 minutes than any other Eredivisie player, while only two players directed more passes forward per 90 minutes.
"Those numbers underline Martinez's ability to play through opposition lines but he is similarly adept at switching the play and picking out team-mates over longer distances. At Ajax last season, no player averaged more successful long passes per 90 minutes.
Voted Ajax's player of the year for his role in their Eredivisie title triumph last season, Martinez stands at just 5ft 9ins, making him small for a centre-back.
"Last season at Ajax, he made more headed clearances (29) than any other player and won 79 of his 112 aerial duels, giving him a success rate of 71 per cent and putting him second only to Harry Maguire among Manchester United and Arsenal's current centre-backs.
"Martinez can expect to face more exacting opponents in the Premier League, of course, but he is also helped by a sound reading of the game. He is known for anticipating strikers' runs and positioning himself smartly to make tackles and interceptions.
"Those qualities, coupled with his versatility and technical prowess, made him all the more alluring to Premier League suitors."