The Frenchman was expected to be in the matchday squad for the final Premier League game of the season with Mourinho rotating in preparation for next Saturday's FA Cup final.
He then sarcastically hit out at his critics as he suggested the negativity around the team was not justified: "If you want to be negative, you can be negative until the point that you can say that Scott McTominay is not good enough", he said.
United's final English Premier League game is at home to Watford on Sunday.
Carrick, who is unlikely to be picked for Saturday's FA Cup final against Chelsea on Saturday and will assume a coaching role at United next season, was treated to a guard of honour by both teams before kick off.
"I look forward to working with him".
"Martial is injured", said Mourinho. In his final Old Trafford match, the 36-year-old gave us all one last reminder of how much of a Rolls Royce he was, as Paul Scholes once described him. Luke Shaw has failed to impress manager Jose Mourinho despite several chances, and with defenders Matteo Darmian and Daley Blind also set to leave the club, the Portugese has had to rely on converted defender Ashley Young to deputise in the absence of a better option.
"I have nobody in the world of football ready to be my assistant manager, so I prefer to educate people to structure my staff in a way where there is education and improvement". Midway through the half, Old Trafford rose as one in support of Sir Alex Ferguson as he continues his recovery in hospital following his brain haemorrhage last weekend. He had treatment in the morning at the training ground and he stayed away [today]. I know them better than anyone.
Watford manager Javi Gracia believes he'll remain as manager next season. On his 464th appearance for United, Carrick played a delightful ball over the top to find Mata, who unselfishly squared the ball to Rashford for a simple tap-in to make it 1-0 to the hosts.
Since Sanchez arrived in January, Rashford has started fewer games for United and it shows in his goalscoring record.
Later, a Rashford pot-shot sailed over the bar and Watford had a mini-flurry in and around United's area, before Carrick's farewell.