Mourinho reunion a reminder of how little has changed for mediocre Man Utd
United's current manager Erik ten Hag secured a stay of execution with a 2-1 victory over Brentford on Saturday to snap a five-game winless run.
But the Dutchman remains under intense pressure as United languish in the bottom half of the Premier League.
With just two points from their opening two Europa League games, an embarrassing defeat at the hands of Mourinho on Thursday would be another damaging blow in Ten Hag's fight for survival.
United had turned to Mourinho in 2016, hoping the self-styled 'special one' could rival Pep Guardiola at Manchester City and Jurgen Klopp at Liverpool.
During his two-and-a-half years at Old Trafford, Mourinho did add to his trophy haul by winning the League Cup and Europa League in his first season in charge.
In his second season, United finished second to Guardiola's rampant City, who set a Premier League record with 100 points.
Things quickly unravelled as the former Chelsea boss was dismissed by United before Christmas in his third campaign.
Given the turmoil around Old Trafford throughout his reign, Mourinho later stated that second place with United in 2017/2018 was among "the best jobs of my career".
That comment was shrugged off as typical bluster from Mourinho, who has made outlandish comments his trademark during three decades managing a number of Europe's top clubs.
Yet, Ole Gunnar Solskjaer, Ralf Rangnick and Ten Hag have passed through the Theatre of Dreams since then without ever restoring United to their former glory.
Six seasons on, the 81 points Mourinho achieved remains by a distance United's best Premier League performance in the 11 years without a title since Alex Ferguson retired in 2013.
That barren run shows no sign of ending anytime soon, with City and Liverpool still streets ahead of United.
"It's not just about this season, it's since we won the last league in 2013, the club has been like in a chaos," former United defender Patrice Evra told the BBC.
'He is a winner'
Ten Hag has at least brought trophies back to Old Trafford after a six-year drought.
But a League Cup triumph in 2023 and shock FA Cup final victory over City in May have barely papered over the cracks of his reign.
Into his third season in charge, there is still little evidence of Ten Hag imposing a recognisable style of play despite spending nearly £600 million in the transfer market, much of which has reunited him with a number of his former Ajax players.
The years since the acrimonious split between United and Mourinho have also not been kind for the latter.
He returned to English football at Tottenham, where he failed to win a trophy for the first time since a short stint at Uniao de Leiria at the beginning of his managerial career.
Mourinho did have silverware to show for his two-and-a-half years at Roma as he lifted the inaugural Europa Conference League in 2022.
But after a run to the Europa League final a year later, he once again departed in rancour when he was sacked in January.
That paved a way for his first foray into the frenzied environment of Turkish football.
More fireworks do not seem far away with Fenerbahce eight points behind Istanbul rivals Galatasaray at the top of the Turkish Super Lig.
But United's visit gives the 61-year-old the big match stage he craves to answer his critics, not least those who turned against him during his time at United.
"It's a big game for both of us," said Ten Hag earlier this week.
"He is a winner. He has won so many trophies and, I think, is an example for many managers. So I really enjoy to play against him."
Ten Hag can ill afford Mourinho to be the winner come Thursday to avoid fuelling the speculation over how long he has left in the Old Trafford hot seat.
