Manchester United have finally confirmed the signings of Ajax defender Lisandro Martinez and Danish midfielder Christian Eriksen. Martinez joined the club in a £46 million deal, while Eriksen, who was a free agent after his stint with Brentford in the Premier League last season, arrived on a free transfer.Both players were persuaded by new boss Erik ten Hag to join him at Old Trafford. While Martinez played under him at Ajax and knew his philosophy, Eriksen was convinced after a short chat with him.Martinez's deal wasn't easy as Manchester United had to fight off Arsenal in the race to sign him. The Eredivisie club also played hardball on the transfer fee. After rejecting the initial bid of £37 million, Ajax finally agreed upon £46 million. The Argentine defender has signed a five-year deal with the Red Devils, as reported by TheMirror.Fabrizio Romano@FabrizioRomanoLisandro Martínez to Manchester United, here we go! Full agreement in place between Man United and Ajax for package up to €55m. Lisandro will sign until 2027, documents now approved. #MUFCDeal done - meeting in Amsterday on Wednesday was the key step. Ten Hag, big factor.20117535684Lisandro Martínez to Manchester United, here we go! Full agreement in place between Man United and Ajax for package up to €55m. Lisandro will sign until 2027, documents now approved. 🚨🔴 #MUFCDeal done - meeting in Amsterday on Wednesday was the key step. Ten Hag, big factor. https://t.co/qyYskmgNMUWhile a verbal agreement was made with Christian Eriksen a week ago, his signing was made official on Friday. The Danish international took his time considering other offers but then decided on a move to Old Trafford.Fabrizio Romano@FabrizioRomanoOfficial, confirmed: Christian Eriksen joins Manchester United! Contract valid until June 2025. 🤝 #MUFC“Man United is a special club, and I cannot wait to get started. Ten Hag is a fantastic coach. Having spoken with him, I am even more excited for the future”, Eriksen says.12004716315Official, confirmed: Christian Eriksen joins Manchester United! Contract valid until June 2025. 🇩🇰🤝 #MUFC“Man United is a special club, and I cannot wait to get started. Ten Hag is a fantastic coach. Having spoken with him, I am even more excited for the future”, Eriksen says. https://t.co/g40SSK2URaMartinez and Eriksen will become new signings in the Ten Hag era as the Dutchman continues to rebuild the squad. Manchester United have already signed left-back Tyrell Malacia (£13 million) from Feyenoord.The Red Devils have struggled a lot in defense and midfield in recent times, most of which were down to poor signings and management. However, having secured Martinez and Eriksen, United supporters can feel optimistic about the future.Let's look at three things that Martinez and Eriken will bring to Manchester United.Lisandro Martinez1# Complete DefenderManchester United v Tottenham Hotspur - Premier LeagueMartinez is a left-footed ball-playing defender who can easily partner Raphael Varane or Harry Maguire at the back. Both Varane and Maguire lacked the pace to stop quick flowing attacks. Martinez can solve that problem, he is pacy, solid and a good tackler who can stop fast counter attacks.Despite his short frame of 5ft 9in, Martinez is good in the air. He has won more areal duels per 90 than Harry Maguire last season, according to talkSPORT. However, it will be tough for him to perform in the Premier League, where the average height per player is about 6ft.2# VersatileArgentina Training SessionBefore becoming a defender, Martinez used to play as a defensive midfielder. Ten Hag has even used him as a midfielder in their time together at Ajax.His passing ability along with his eye to read opposition attacks make him a versatile player. Manchester could benefit from him if Scott McTominay or Fred get injured. Martinez can also play at left-back if the team requires it.3# Winning MentalityThe current Manchester United squad needs to boost their mentality and morale. By signing Martinez, Ten Hag might have done just that as the Argentine was a winner with his former side Ajax.Brazil v Argentina: Final - Copa America Brazil 2021The Argentine has won two Eredivisie (2020-21 & 2021-22) titles with Ajax and was named their player of the year last season. He has also won the Copa America (2020-21) with Argentina. His inclusion in the squad could push other players to up their standards.Christian Eriksen#1 StabilityManchester United v Brentford - Premier LeagueChristian Erkisen is a deep lying playmaker. His short passes and vision to make a decisive long pass into the final third make him a threat for the opposition. Despite being an attack-minded player, Eriksen is quick to sniff off any danger and can contribute defensively too. He keeps the team glued together.Along with that, his ability to control the game's tempo will stabilize Manchester United's midfield, which often looks out of structure.Fabrizio Romano@FabrizioRomanoOfficial, confirmed. Paul Pogba signs his contract as new Juventus player, new deal worth €8m net plus add ons until June 2026. Commission around €2.5m. #JuventusPogba, back at Juventus on a free transfer after being sold for €100m six years ago.359042531Official, confirmed. Paul Pogba signs his contract as new Juventus player, new deal worth €8m net plus add ons until June 2026. Commission around €2.5m. 🚨⚪️⚫️ #JuventusPogba, back at Juventus on a free transfer after being sold for €100m six years ago. https://t.co/CmhXTO0XUHHe could provide Manchester United's midfield with the balance they were looking to get from Paul Pogba, who joined Juventus on a free transfer this summer after the expiration of his contract.#2 Premier League ExperienceBefore joining Inter Milan in January 2020, Eriksen spent seven seasons with Tottenham Hotspur. He's not new to the league and understands what it will take to perform at the highest level.He has been one of the top five assist makers in the Premier League since 2013-14, with 66 assists to his name. He is just behind Kevin De Bruyne, who leads the table with 86 assists.Football on BT Sport@btsportfootballThe numbers DO NOT lie... Christian Eriksen is right up there with some of the Premier League's top assist makers A superb signing for Erik ten Hag and Man United 🤩2360155The numbers DO NOT lie... 📊Christian Eriksen is right up there with some of the Premier League's top assist makers 💪A superb signing for Erik ten Hag and Man United 🤩 https://t.co/2sGjPBrN8m#3 InspirationChristian Erkisen is a born fighter. Not many would have thought that he would return after his horrific cardiac arrest at Euro 2020. The Dane, however, proved everyone wrong and returned to the top level of football in just under a year.Denmark v Belgium - UEFA Euro 2020: Group BHe has played for Denmark since his return and joined Brentford on a six-month loan in January last season. He is the first professional footballer with an Implantable Cardioverter Defibrillator (ICD) fitted in his heart. It's a device that can shock and reset the heart after a cardiac arrest.Despite his condition, Eriksen made four assists and contributed a goal in 11 games for Brentford.Everyone at Manchester United and around the globe can take inspiration from him story and overcome any obstacles in life and in football.All in all, Manchester United have done good business in securing two excellent players who will address the key areas the Red Devils are struggling in.