Protected by the luck and football gods
The Red Devils headed into the clash in desperate need of a win to keep the pressure on City, but Pep Guardiola's side dominated from the first whistle which was rewarded with David Silva's opener before Marcus Rashford's equaliser deep into first-half extra-time.
The Citizens regained their lead with Nicolás Otamendi's scruffy effort, United were brilliantly denied a point in the dying minutes as Ederson produced an excellent double save from Romelu Lukaku and Juan Mata.
However Mourinho felt that they should have had a penalty late on when Ander Herrera went down under the challenge of Otamendi which Oliver not only waved away but booked Herrera, and Mourinho stated his disappointment and sympathy for Oliver who he believed made an "important mistake".
“Manchester City are a very good team and they are protected by the luck," Mourinho stated post-match. "And the gods of football are behind them."
“My first reaction is I feel sorry for referee Michael Oliver," the coach admitted. "Because he had a very good match but unfortunately he made an important mistake."
“I feel sorry for Michael Oliver because I think he had a good game," he proclaimed. "I would say very good game - his assistants the same."
"I think they come with the intention to make the perfect work," Mourinho added. "Which they almost did."
It is a significant distance now
Sunday's defeat ensured that City became record breakers with their 14 consecutive league victory, but more significantly it opened up an 11-point gap at the summit of the table over The Red Devils.
Many had previously stated that the title will be at the Etihad Stadium come May, and though Mourinho admitted that it is a "significant distance" between the two sides but can only look towards winning Wednesday's clash with AFC Bournemouth.
“It is a significant distance [to City now]," he said when asked if he believed the title race was over. "I don’t know [if we can make it up]."
"I know we can win next Wednesday [against Bournemouth]," Mourinho concluded. "We can work and fight for it. That is the only thing I say.”