Jose Mourinho can think what he likes about the decision that never came in the build up to Watford's first goal but nothing that comes out of his mouth should detract from the fact that his team were well-beaten at Vicarage Road.

The Miguel Britos challenge on Anthony Martial was robust - and the Frenchman was still feeling the effects of a head injury moments before - but it was by no means an obvious foul. Michael Oliver - the referee - was well within his rights to wave play on and permit the goal from Etienne Capoue to stand. 

"It was not an action to end with [Martial] in the hospital, it was an action to end in a free kick," was Mourinho's assessment.

From there, United played with a persecution complex. Mourinho - as well as his assistant Rui Faria - collared the fourth official Stuart Atwell and persistently made him aware of their feelings regarding the decision to award the goal. On the field, Mourinho's players bristled. There was more bite in their challenges - a petulant defiance - as if they were daring the referee to whistle against them. 

There was a gap in the standard between the teams - Walter Mazzarri again facing his old foe Mourinho - but it was the hosts and not the 20-time English champions who looked more assured about what they were doing. They seemlessly flitted between shapes and formations - always aware of what needed to be done - while United's number could not add any sort of extra dimension to their play. 

Paul Pogba was loosened up slightly - playing to the left of a midfield three with Marouane Fellaini at the base - and although he hit the crossbar with a good first-half effort he is still giving performances far beneath those expected from an £89m player. 

Wayne Rooney - meanwhile - is not repaying the manager's faith. He was afforded midweek off in preparation for his tie but again could not stand the pace. He has played decently in the Premier League this season - despite the negative attention on his displays - but here he was bad.

He gave the ball away, ran it out of play and had to be vocally encouraged on more than one occasion by his manager to engage in the press. Rooney is a player of the highest class but coasting cannot be tolerated - particularly at a team which is under-performing collectively. He roared at his colleagues after the first goal but he was doing so when he himself was playing as badly as anyone else.

Mourinho can only point to Marcus Rashford as a bright spot - the boy wonder whom he asked to prove himself all over again. After becoming the story of United's season last term, he was shunted back to the bench this time around with Mourinho making him strain at the leash before letting him loose against Hull City. Here he started - and scored a goal which looked to have rescued a result for an ordinary-looking United. 

Zlatan Ibrahimovic is like an endangered species in this United team - he is having to go hunting in unfamiliar habitats for his supplies. He dropped into midfield to give Rooney a lesson in carrying the ball forward in the run-up to the goal, playing a one-two with Rashford before hitting the 18-year-old with the cross. It was eventually bundled in and Rashford wheeled away with the ball under his arm. 

It took Watford a while to rouse themselves from that sucker punch - a better team than United would have capitalised - but regained enough composure to earn their three points. 

Juan Camilo Zuniga again showed the deficiencies in the United shape when he latched onto a Roberto Pereyra pull-back to restore the Hornets’ lead. He had barely been on the field for a minute and neither Mourinho – nor his players – had decided who was going to mark him. His finish – under no pressure – was accurate.

The penalty rounded things off well for Watford – with Troy Deeney deserving of his place on the scoresheet and there was chaos in the United ranks by then. They were in total meltdown.

Pep Guardiola aimed a pointed dig at his old rival Mourinho yesterday when he said Bournemouth were the best team Manchester City had faced so far this season. For organisation, for pressing and for ideas, Eddie Howe’s team came out on top in the Catalan’s eyes. It might have sounded harsh towards a United side who had won three leagues games from three but looks all the more accurate now.

The bounce is over; United and Mourinho have problems to solve that currently look beyond their capabilities.