The Spain international has been consistently one of Manchester United’s best players under Sir Alex Ferguson, David Moyes, Louis van Gaal and Jose Mourinho.
De Gea has often been the sole positive in the darkest moments under Moyes and Van Gaal, as well as impressing during some negative Manchester United performances this term.
In addition, La Liga giants Real Madrid have been regularly linked with a swoop to sign the Spanish shot stopper over the past three or four summer transfer windows.
However, Manchester United have managed to keep De Gea at Old Trafford despite the lure of a possible return to the Spanish capital.
The Red Devils goalkeeper struck a disconsolate figure on Tuesday night after Manchester United suffered a surprise 2-1 loss to Sevilla in the second leg of their Champions League last-16 clash.
Former Arsenal defender Keown believes De Gea is the only Manchester United player emerging with credit during a mixed run of results in the 2017-18 season.
“The only player really fulfilling his potential is David de Gea,” Keown told the Daily Mail.
“He is the most overworked goalkeeper in the top five, with United facing more shots in the Premier League this season than any of their main rivals for the top four.”
Manchester United finished in sixth place in the Premier League table last term but won the Europa League and the League Cup.
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