Manchester United have signed Serbia midfielder Nemanja Matic from Premier League champions Chelsea on a three-year contract with an option to extend for a further year, both clubs said on Monday.Financial terms of the deal were not disclosed, but British media reported that United paid between 40 million ($52.48 million) and 50 million pounds to reunite the 28-year-old midfielder with manager Jose Mourinho.”Nemanja is a Manchester United player and a Jose Mourinho player. He represents everything we want in a footballer; loyalty, consistency, ambition, team player,” Mourinho said in a statement.”I would like to thank him for his desire to join us because without that, it would be impossible to have him here. I am sure our players and supporters will love him. A big welcome to our new number 31.”A beast in midfield.Nemanja Matic is a red. #ACE17 #HereToCreate pic.twitter.com/MCSxbpobgl- adidas Football (@adidasfootball) July 31, 2017Mourinho signed Matic when he was in charge of Chelsea in 2014. Matic, who originally joined Chelsea in 2009 before moving to Benfica in 2011, became an influential part of Chelsea’s title-winning side under Mourinho in 2014-15.”To work with Jose Mourinho once again was an opportunity I couldn’t turn down,” Matic said.”This is a very exciting time for the club and I am looking forward to playing my part in creating more history for this great club.”Watch the full interview with our new signing, Nemanja Matic, exclusively on #MUTV in 10 mins! https://t.co/pTjtU90C91 #MaticIsRed pic.twitter.com/3fqMbL39eZadvertisement- Manchester United (@ManUtd) July 31, 2017Matic’s arrival followed Mourinho’s unsuccessful move for Tottenham Hotspur’s Eric Dier as United seek to mount a serious Premier League challenge for the first time since the departure of Alex Ferguson as manager in 2013.Matic made 40 appearances in all competitions for Chelsea last season as Italian Antonio Conte marked his first season in charge of the London-based club by winning the league.However, Chelsea’s signing of Monaco midfielder Tiemoue Bakayoko in this transfer window was an indication that Matic could have struggled for game time next season.United have also signed defender Victor Lindelof from Benfica and striker Romelu Lukaku from Everton.