Manchester City are locked in a battle with local rivals Manchester United to sign highly rated Porto defender Eliaquim Mangala.The French defender has been in superb form this season for Portuguese side Porto sparking a flurry of interest across Europe from Real Madrid, Barcelona, Chelsea, as well as the Manchester clubs.FDN can reveal City’s sporting director Txiki Begiristain flew to Portugal on Thursday night to discuss a potential move for the star with the Etihad outfit believing they will trump United by offering more money and being able to offer the 23-year-old Champions League.Mangala was in action for Porto as they faced Sevilla in the Europa League and with the defender scoring the only goal of the game to cap another fine display.The star has a current contract with Porto until 2016 and is said to have a release clause of 42m, which Porto and City are understood to have negotiated.Watch Chelsea v Stoke on Saturday and Arsenal v Everton, West Ham v Liverpool on Sunday. 24-hour Sky Sports day pass for only 9.99. No contract.