Mourinho lamented that his staff had been left in the dark about the fitness of key members of his squad.
Steven Gerrard's future at Liverpool may be in doubt but the captain turned back the clock to score in a 3-1 victory at bottom side Leicester City in the Premier League on Tuesday.
Two goals from Marcus Rashford gave United a 2-0 lead after 24 minutes and Juan Mata went close to a third with a bicycle kick inside the area. Liverpool had plenty of possession after the break but apart from Eric Bailly's 66th minute own goal, they created few real chances.
Manchester United suffered their third defeat in eight days as Watford handed Jose Mourinho his worst run as a manager in a decade. Goals from Etienne Capoue, Juan Zuniga and a late penalty from Troy Deeney overwhelmed the visitors, who had levelled with a solitary strike from Marcus Rashford.
German midfielder Bastian Schweinsteiger is unlikely to play for Manchester United this season, manager Jose Mourinho said on Friday.
A third place finish at the World Cup on Saturday leaves a strong legacy for Belgian football, coach Roberto Martinez said
Belgium and England have already met during the World Cup in a match both teams seemed reluctant to win and on Saturday they will face each other again in a game they both seem reluctant to play. The two sides must pick themselves up and dust themselves down after suffering the crushing disappointment of semi-final defeats to play for the modest prize of third place in a fixture often criticised as pointless.
The simplicity of football was again emphasised as France secured a place in the World Cup final from a basic set- piece.
A compelling cast of players, two attacking teams propelled by great pace and a clash between neighbours to boot.
England and Belgium, already qualified from World Cup Group G, meet on Thursday in what Belgian midfielder Marouane Fellaini says could be a "strange match". Depending on the outcome of other games, it may not be an advantage to finish top of the group, but both sides insist they won't take such calculations into account.
Mourinho was also adamant that it was crucial to United's ambitions to keep the 28-year-old Spain international, who has been linked with French champions Paris St Germain.
Ajax to face United in final despite defeat at Lyon
Louis van Gaal accused his Manchester United players of being out-fought in a 3-0 defeat at Everton.
Blames mid-week Champions League win against Juve for 'mental pressure'
'We have to be hard in the tackles, we have to try to dominate the game and score the goals when we create chances. We will see what happens'
None of Manchester United's injured players are likely to be fit for the next Premier League match against Newcastle United, manager Louis van Gaal said on Tuesday.
Following is reaction to the 2022 FIFA World Cup draw, which was held at the Doha Exhibition and Convention Center in Qatar on Friday.
'A new caretaker manager will be appointed until the end of the current season, while the club conducts a thorough recruitment process for a new, full-time manager'
Much-fancied Belgium fought back from a goal down to score twice in the final 20 minutes and earn a hard-fought 2-1 victory over gutsy Algeria in their World Cup Group H opener on Tuesday.
Zlatan Ibrahimovic's winner ensured that Jose Mourinho's reign at Manchester United got off to a winning start as the FA Cup holders beat champions Leicester City 2-1 in England's Community Shield season curtain-raiser at Wembley on Sunday. Ibrahimovic leapt above Leicester captain Wes Morgan in the 83rd minute to head Antonio Valencia's cross beyond Kasper Schmeichel, marking his official debut with a decisive contribution.
It was not a day for FA Cup romantics as Manchester United scrambled past Sheffield United and minor league Eastleigh came within a whisker of causing the third round's only genuine shock.
Didier Deschamps is confident he has prepared his players for any tactical surprises his opposite number Roberto Martinez might spring
Belgium's Eden Hazard is making the strongest bid for that crown.
Belgium coach Roberto Martinez said he was the "proudest man on earth" and lavished praise on his "underdog" team for having the belief to upset five-times champions Brazil on Friday to reach the World Cup semi-finals for only the second time.
Eden Hazard is admired for his attacking flair, ability to run at defences and finishing but it is his maverick genius that sets him apart.
Manchester United will be without skipper Wayne Rooney, Marouane Fellaini, Michael Carrick and Anthony Martial for their visit to Watford on Saturday when the Premier League resumes after the international break.
Manchester United are feeling the pressure ahead of their Champions League qualifier against Club Bruges on Tuesday, according to manager Louis van Gaal.
Chelsea a 1-0 win over Manchester United in a compelling Premier League clash on Sunday
Liverpool and Manchester United's globe-trotting squads must shake off the effects of international duty for one of English football's most eagerly-anticipated clashes on Saturday.
Neymar has been included in Paris St Germain's squad for Wednesday's Champions League game against Bayern Munich after recovering from a foot injury, coach Unai Emery said on Tuesday.
For however much or little it counts, Belgium have history on their side in not having lost to the Irish for 50 years, which includes beating them by a single goal in the playoffs to win a place at the 1998 World Cup in France.
Images from the English Premier League matches played on Saturday
Belgium struck early and held off a late Brazil fightback to send the five-time champions tumbling out of the World Cup with a 2-1 victory in an end-to-end thriller on Friday that earned them a semi-final against France.
Belgium play in a second successive World Cup quarter-final, looking to reach the semi-finals for the second time after they advanced to the last four in Mexico 32 years ago.
Belgium passed a test of character with a display of true grit that bodes well for a World Cup quarter-final against Brazil, coach Roberto Martinez said after they came from 2-0 behind to beat Japan 3-2 in injury time.
Manchester United manager Louis van Gaal was at his bizarre best again after his team's 1-1 Premier league draw with Leicester City as he complained that a hair-pulling incident during the match was only acceptable in 'sex masochism'.
Belgium hammered the final nail into Egypt's halting World Cup warm-up campaign with an assured 3-0 win in Brussels on Wednesday that settled some nerves among the fancied hosts.
Louis van Gaal praised his side's attacking display against West Ham United but said they 'forgot to score goals' after a fourth 0-0 draw in their last six home matches on Saturday.
IMAGES from the English Premier League match played between Manchester United and Liverpool at Old Trafford on Saturday