Mata, Martial and Sanchez scored for United after Kennedy and Mutō gave the visitors a commanding lead after eleven minutes.
Coming into the game, there were talks about a Mourinho sack irrespective of the result. And it was already looking bad for the Portuguese very early on.
The Magpies took advantage of a disjointed United back-line in the opening minutes to put themself in a good position.
They took the lead just after seven minutes when Ayoze Pérez found Kenedy in attack. The Brazilian turned Ashley Young inside out before finding the bottom corner.
Yoshinori Mutō made it 2-0 for the visitors four minutes later when he fired past De Gea after some fine work in the box.
Benitez men took their two-goal lead into the break as they hoped it would be their first win of the season.
United came out strong in the second half as they sort to rescue their season.
The visitors stood firm for majority of the game, denying United a way back in and causing problems at the other end.
But Juan Mata pulled one back with an exquisite free kick with twenty minutes left on the clock to kick-start the come-back.
United got their equalizer seven minutes later when Martial placed his shot low after a fine one two with Pogba.
The come-back was eventually completed when Sanchez rose highest to head Young’s cross into the net in additional time.
There have been talks of the players wanting the manager out but this win definitely takes some pressure off Jose Mourinho’s shoulder and tells well of the team’s character.
United’s next game is against high-flying Chelsea at Stamford Bridge after the international break. One they’d need to play another exceptional game to get any result.