Manchester United have completed the signing of defender Marcos Rojo from Sporting Lisbon with winger Nani heading in the opposite direction on a season-long loan.
The Argentina international will cost United £15.98million and moves to Old Trafford on a five-year deal.
"Manchester United is delighted to announce the signing of defender Marcos Rojo from Sporting Lisbon for a fee of 20million euros, with Nani joining the Portuguese club on a season-long loan," read a statement from United. "Marcos joins on a five-year contract."
Rojo is equally comfortable at centre-back as he is at left-back and played all 120 minutes of July's World Cup final as Argentina lost to Germany after extra-time in Rio de Janeiro.
The 24-year-old began his career in his homeland with Estudiantes de la Plata and spent a single season with Spartak Moscow before moving to Sporting in 2012.
He also has 28 caps for his country and cannot wait to play his part in Louis van Gaal's new era at United.
"It is such an honour to say that I now play for Manchester United," he said. "The Premier League is the most exciting league in the world and to have the chance to play in it for the world's biggest club is a dream for me.
"I am young and am very keen to continue to learn the game, so playing for such an experienced technical coach as Louis van Gaal is a fantastic opportunity for me.
"I have joined United to work hard with my team-mates to win trophies and I know that the manager shares that ambition."
Rojo joins Ander Herrera and Luke Shaw as Van Gaal's third high-profile signing since taking over earlier in the summer and the Dutchman believes he will be a useful addition as the former Bayern Munich boss implements a new 3-5-2 formation at Old Trafford this term.
"Marcos is a very gifted defender," he said. "He has played at the highest level in world football and can play either as a central defender or left-back.
"He has ability, physical strength and a willingness to learn that means he has a very bright future ahead of him.
"He had a very strong World Cup and has been playing in Europe for a couple of years now. He is a very good addition to the team."
United lost centre-backs Rio Ferdinand and Nemanja Vidic alongside left-back Patrice Evra this summer and Rojo will add to a defensive unit which was largely criticised following the defeat to Swansea at the weekend.
The move for Rojo had been complicated by a row between Sporting and a third-party ownership group, while the player upset his employers by initially refusing to train in a bid to push through the deal, although he later apologised and returned to work.
The 27-year-old Nani, who moved to Manchester seven years ago, previously spent four years as a Sporting player after leaving Real Massama in 2003.
He has made 228 appearances in all competitions for United, scoring 40 goals, but has rarely been a regular starter during his time in the Barclays Premier League.
Meanwhile, United have dismissed reports linking them to unsuccessful bids for Thomas Muller and Marco Reus.
The club insist rumours of failed moves for the German pair are untrue, with a United spokesman telling Press Association Sport: "It is not true that we made offers for Muller or Reus at any stage."
Marouane Fellaini looked set to be making a move out of the north west but that may now have been scuppered with the Belgian sustaining an injury in training.
United have not commented on the extent of the injury, but pictures in The Sun showed the 26-year-old on crutches with his left foot in a protective cast.
Fellaini had been expected to tie up a loan move to Serie A club Napoli before the end of the transfer window and that move is clearly now in doubt.