Mourinho dug out England full-back Shaw at the weekend, claiming he was “a long way behind” other United defenders in terms of focus and ambition.
And Old Trafford legend Neville, who part of the England set-up when Shaw broke through at international level, has told the former Southampton star to fight back against Mourinho’s damaging comments.
Shaw, still only 21, has not played for United since last month’s 1-1 draw with Bournemouth and he has joined Henrikh Mkhitaryan, Chris Smalling and Anthony Martial in being publicly criticised by his manager this season.
United take on Everton on Tuesday night five points outside the top four and with just 10 games left to close the gap.
And Neville believes Shaw can only respond one way if he is to save his United career, saying: “The harshest possible comments you can possibly have levelled at you are that you don’t train hard enough – and Jose has levelled that at Luke.
“I worked with Luke for two or three years with England, and this is a sensational talent who’s got many years ahead of him.
“He’s had major injury problems, which I think has been his biggest problem – the idea of being out quite a lot.
“But he’s got to respond, this is it now. He’s at Manchester United – you’ve got to make it work, you don’t want to leave that club.
“Ultimately, it’s how Luke Shaw takes those words on. Does he think, ‘That’s it, that’s the end of me’? Or does he think, ‘I’ll show you’ – and I hope it’s the latter.
“I hope he feels as though ‘I’m going to get this right, I’m going to prove this man wrong.’
“I do believe in him as a talent, but he’s really got to do it now because the manager is throwing down the gauntlet and saying, ‘Look, you need to improve.’
“There’s been talk about his lifestyle, but I saw him with England and that was never a problem with him personally. I saw him train quite well, I saw him work hard, I saw him do the right things.”