Reports on Saturday morning claimed Mourinho would be dismissed as United's manager this weekend, regardless of the result against Newcastle.
Neville's incredible four-minute rant highlighted the fact that United had seen four managers since the retirement of Sir Alex Ferguson, suggesting that the problems came in the club's boardroom.
Manchester United v Newcastle can be viewed by UK residents on BT Sport 1 and BT Sport 1 HD, which is channel 430 or 408 respectively on Sky and channel 531 and 527 respectively for Virgin Media users. I said last season was a fantastic season for us.
Marcos Rojo, Jesse Lingard and Ander Herrera all missed the Champions League group stage against Valencia in midweek and have not recovered in time to face the Magpies.
"No, it's exactly the same [squad]", he said, when asked whether anyone had recovered.
"I think he's got some really good quality in the squad who are really low on confidence".
"I have to assess Fede (Fernández) and (Paul) Dummett", The Newcastle official website quote him as saying.
Ashley Young could return after a minor knock, but Mourinho will be without three of his key players.
But, clearly, some of the boys - Marcus Rashford was sad on the pitch.
Also in contention for the Red Devils are Phil Jones, Andreas Pereira and Diogo Dalot.
"And if you want something more, in pre-season I also said that this season was going to be very hard". The Brazilian Chelsea loanee has struggled to replicate his form in black and white toward the end of last term, having failed to create a single chance in the league.
But his buzz word was "man-hunt".
Newcastle, who began the day second-bottom in the table on goal difference, had not held a lead in any league game this season before Kenedy opened the scoring in the seventh minute.
It stunned the United fans in attendance and forced Mourinho into a series of tactical substitutions, making the first one less than 20 minutes into the game.
Glazers are known to support managers at the club until things go completely out of hand.
Zidane would likely be a popular choice given his incredible European success at Madrid, and the eye-catching brand of football he had the Spanish giants playing, a stark contrast to the pragmatic style United fans have become accustomed to under Mourinho.
That was the first time in the Premier League era that United had conceded two goals, at home, in the opening ten minutes of a game.