Sanchez has completed his move from Arsenal to Manchester United with Mkhitaryan moving in the opposite direction.
Swap deals are something of a rarity in elite football, and here is a look back at five other high-profile player-swaps and how they worked out for those involved.
Zlatan Ibrahimovic and Samuel Eto’o
Zlatan Ibrahimovic signed a five-year contract with Barcelona in 2009 to end his sensational three-year spell at Inter Milan, with the Spaniards paying £40million and sending their top scorer in La Liga Samuel Eto’o to Italy in return. In one of the rare disappointments of his glittering career, Ibrahimovic spent just a year at the Nou Camp before joining AC Milan in 2010 after falling out with Pep Guardiola. Eto’o, meanwhile, thrived in Serie A winning the treble - Serie A, UEFA Champions League and Coppa Italia - under Jose Mourinho.
Ashley Cole and William Gallas
Ashley Cole’s deadline day move to Chelsea from rivals Arsenal in 2006 brought to an end one of the most bitter transfers of the Premier League era and saw William Gallas go the other way, along with a fee of £5million. Cole, a member of Arsenal’s ‘Invincibles’, added another league title with the Blues as well as four FA Cups and the Champions League in 2012 in a successful eight-year spell. Gallas won nothing with the Gunners and moved to Tottenham on a free transfer in 2010.
Jermain Defoe and Bobby Zamora
Tottenham emerged with the only major signing on deadline day in January 2004 when they landed Jermain Defoe from relegated West Ham in a £7million deal which saw Bobby Zamora move in the opposite direction. The transfer worked for both clubs, Defoe scoring 91 Premier League goals over two spells with Spurs and Zamora hitting the winner in the 2005 Championship play-off final which saw West Ham secure their return to the top flight.
Andy Cole and Keith Gillespie
A shock move in 1995 saw Newcastle swap their star striker Andy Cole for £6million plus Manchester United winger Keith Gillespie. At Old Trafford, Cole won five Premier League titles, two FA Cups and the Champions League – including the treble in 1999 – and scored a total of 121 goals in 275 games. Gillespie was also a success with the Toon, becoming a key figure in Kevin Keegan’s entertaining side which twice finished runners-up to United.
Kevin Davies and James Beattie
Roy Hodgson was in charge of Blackburn in 1998 when they paid Southampton £7.5million for striker Kevin Davies and also threw in James Beattie. But Davies managed just one league goal all season as Rovers were relegated, while Southampton beat the drop with Beattie scoring five times. Davies rejoined Saints a year later, this time in a swap with Egil Ostenstad. Beattie stayed at Southampton until 2005, scoring 68 goals.