The Red Devils lost 3-1 to West Ham United at the London Stadium last weekend as Manchester United slumped to their third defeat of the Premier League season.
The 20-time English champions were thoroughly outplayed by the Hammers despite Mourinho opted to go for height and power in the middle of the park.
Bizarrely, Mourinho decided to start with the trio for the visit of La Liga side Valencia in their second Champions League group stage on Tuesday night.
The Red Devils were devoid of ideas in a disappointing performance in Manchester United’s 0-0 draw with Valencia at Old Trafford to heap more pressure on Mourinho.
Fellaini and Matic are defensive-minded players tasked with protecting Mourinho’s suspect defence, although the duo have disappointed in recent weeks.
Pogba, on the other hand, is seen as a creative force in the middle of the park but the France international has struggled to find consistency.
Former Arsenal defender Keown doesn’t believe Fellaini, Matic and Pogba work as a midfield combination.
Asked by a Daily Mail reader why he described Manchester United’s midfield as “dinosaurs” in Tuesday night’s goalless draw with Valencia, Keown replied in his Ask Keown column:
“Individually, Matic, Fellaini and Pogba are all good players but they simply do not work together.
“All three are big, loping players and lacked the energy and industry someone like Fred would have brought to the side.
“The midfielders all operated independently to one another. Pogba and Fellaini committed themselves high up the pitch and when Valencia were attacking, Matic was overrun. When United wanted to build attacks, Matic was the only option the defenders could pass to.
“It meant that United simply could not build from the back and at times their best option was kicking it long to Fellaini.”
Pogba has proven a particularly controversial figure at Manchester United since his move back to Old Trafford.
The France star has been disappointing and hasn’t paid back the club record fee that Manchester United paid to re-sign the versatile midfielder.
The World Cup winner’s relationship with Mourinho appeared to start to deteriorate after Mourinho left Pogba out of his starting line up for their Champions League clash against Sevilla earlier this year.
Pogba was stripped of the vice captaincy after the French midfielder criticised Mourino’s tactics in the wake of their 1-1 draw with Wolverhampton Wanderers at Old Trafford last month.
The Manchester United number six has been linked with a potential move to La Liga side FC Barcelona in recent months, despite moving to Old Trafford less than two seasons ago.
Pogba has won the Europa League and the League Cup in his first season back at Manchester United.
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