It was a day for goodbyes at Old Trafford, most notably Carrick, 36, who was named captain for the day and granted a guard of honour by both sets of players before kick-off as he brought down the curtain on his dozen years at Old Trafford.
But it was also the end of an era for his manager Jose Mourinho, who had his loyal lieutenant Rui Faria alongside him the dug-out for the final time in a league game, after a partnership dating back 17 years.
Faria, United announced over the weekend, has decided to test the managerial waters elsewhere next season leaving a conveniently Carrick-sized hole in Mourinho’s coaching staff for the next campaign.
“I will organise my coaching staff in a way where the assistant manager figure doesn’t exist,” said Mourinho when asked if Carrick will replace Faria next season.
“I am going to have assistant coaches and the reason is that I think it will be Michael Carrick in the future when he has his badges, his pro license. 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 for when Michael has the pro license badges.”
Among the farewells, more conspiratorially there was also fresh uncertainty over Anthony Martial, the French international who, it is fair to say, has struggled to impress Mourinho on a consistent basis this season.
Mourinho had publicly stated Martial would play against Watford, presumably offering him a last chance to earn a place in the squad for next weekend’s FA Cup Final with Chelsea, but reports claimed the player left Old Trafford soon after reporting for duty at noon.
Mourinho could not speculate whether Martial’s knee injury will allow him to play in the Cup final although the United manager is now confident Romelu Lukaku will be available for the Wembley occasion.
All of which contrasted heavily with Carrick, whose place in Manchester United history was assured long before his farewell performance against Watford yesterday.
After 34 minutes he also provided a poignant reminder of his incredible ability.
Collecting the ball just inside his own half, the former England international lofted a pinpoint pass that floated onto the toes of Juan Mata, behind the Watford defence.
The Spaniard selflessly and intelligently passed it square, and slightly behind, to the on-rushing Marcus Rashford who rolled the ball into the open goal.
It was a rare moment of quality on a day which produced little, at the end of a season in which United, all too often, have been crying out for a player of the calibre of Carrick to unpick opposition defences.
Thankfully, Carrick’s contribution also offered some sort of on-field incident in a meaningless end of season affair which saw Mourinho rest the bulk of his cup final line-up.
One of the stand-in players, goalkeeper Sergio Romero, at least made good use of his opportunity with an excellent first half save that preserved United’s lead.
Daryl Janmaat picked out the unmarked Richarlison with a magnificent cross from the right and his downward header looked destined for the back of the United net until Romero made a stunning dive to turn it away.
From the resulting corner, Gerard Deulofeu shot straight at Romero before a second half which offered even less in terms of goalmouth action.
Mata just failed to connect with Alexis Sanchez’s far-post cross and Marcos Rojo almost gifted the ball to Will Hughes in a dangerous position.
But, after a weak Abdoulaye Doucoure header was comfortably gathered by Romero, there was time for Mourinho to allow Carrick one last accolade, taking him off six minutes from time to a rousing standing ovation, from both sets of supporters.
Romero 6; Darmian 6, Bailly 6, Rojo 6, Blind 6 (Herrera 76, 6); McTominay 6, Carrick 6 (Pogba 84); Mata 6, Sanchez 6, Young 6 (Shaw 59, 6); Rashford 6.
Gomes 6; Janmaat 8, Cathcart 7, Kabasele 6 (Mariappa 20, 6), Holebas 7; Doucoure 7; Deulofeu 6 (Deeney 62, 6), Hughes 7, Pereyra 6, Richarlison 6; Gray 6 (Chalobah 72, 6).
Lee Mason 7