"We were losing 2-0, they created even more chances to score more goals and confidence levels were low".
Mourinho is subsequently expected to be in charge of United's visit to Chelsea after the global break.
"Their problems are too deep-rooted for one half to have sorted them out".
So often criticised for preaching a cautious approach, it was only when Mourinho's men threw caution to the wind when 2-0 down that they began to look like the United of old.
Both players were subbed with the Red Devils two goals down and staring another defeat in the face, which may well have cost Mourinho his job at Old Trafford.
The goals led Mourinho to take Eric Bailly off after just 19 minutes, replacing him with Mata, and his defensive adjustments did not end there.
United's attack did the defence no favours in the 50th minute, with Pogba denied by Newcastle Martin Dubravka from 25 yards despite a deflection and Matic missing the second chance, on an open net, by sending his attempt over the crossbar.
Anthony Martial, at odds with the Portuguese this season, scored the equaliser and Sanchez, left out of the squad against West Ham last week, headed a 90th-minute victor. "All the players committed mistakes that were not normal".
"At half time, I'm sure there were a lot of happy people loving every moment of it, but the team spirit is very strong."
"If I'm honest, yeah, 100% [I could see it turning around], as soon as we came out in the second [half]", he explained to MUTV.
However, that figure would dramatically reduce to just £10m if he sees out the season and United fail to finish in the Champions League positions, which would hit the club's finances.
"We all know one swallow doesn't make a summer", he told the BBC.
However, the attacker earned hero status on Saturday evening when he came off the bench in the second half to fire home the victor for Manchester United against the Magpies.
Alexis Sanchez has justified neither his wages nor his reputation at Manchester United, which means the man who signed him takes the blame.
This time City could deliver the final nail in the coffin.