Keeping David de Gea at the club would be the biggest signing Manchester United could make this summer , says Phil Neville . The Spanish keeper has impressed for Louis van Gaal 's side this season and has heavily been linked with a move to Real Madrid , who are looking for a long-term replacement for Iker Casillas . United have been linked with their own big-money moves for the likes of Gareth Bale and Mats Hummels , but Neville believes the club must concentrate on keeping De Gea at Old Trafford . David de Gea met Man United fans earlier in the week as part of a day organised by the club 's foundation . De Gea punches the ball away during Manchester United 's 1-0 defeat to Chelsea at Stamford Bridge . 'The biggest thing is David De Gea , and keeping him at the football club , ' Neville told the Manchester Evening News . 'From when he first came , to how he is now , I don ’ t think I ’ ve seen a player develop and improve as quickly as him . ' I saw with Cristiano ( Ronaldo ) , I saw the development in terms of his performance , his size , his stature and his physique . 'He ’ s winning football games on his own . Last minutes saves against Everton , Hull , Arsenal away - there ’ s seven or eight occasions where he has won United games which just shows you that he is world-class . '
David de Gea has been integral to Man United 's success this season . Spanish keeper has been linked with a move to Real Madrid in the summer . Phil Neville says keeping De Gea would be best business the club can do . Gareth Bale and De Gea swap ? Pair will likely be Real Madrid team-mates . CLICK HERE for all the latest Manchester United news .