When asked in May 2022 about whether he admired Manchester City and Liverpool, the former United boss infamously remarked that while their rivals were formidable opponents, eras inevitably come to an end.
Ten Hag's era ended at Old Trafford on Monday, with United's controversial 2-1 defeat against West Ham United on Sunday afternoon proving to be the final straw for owner Sir Jim Ratcliffe.
The Dutchman won the EFL Cup in his first season in charge in 2022-23, their first piece of silverware since their Europa League triumph under Jose Mourinho in 2017.
Ten Hag also won the FA Cup last term, deservedly beating Premier League champions Manchester City 2-1 in May final at Wembley.
However, the Red Devils have often floundered in the league under his guidance, finishing eighth in 2023-24 and they are currently in 14th place with just 11 points.
The Dutchman defended his side on numerous occasions, blaming injuries for the team's inability to find consistency, while also brushing off critics who accused him of failing to implement a clear style of play.
Ten Hag's position as boss of United had been under scrutiny for some time, with the club reportedly having scouted a number of candidates in the summer as potential replacements should the Dutchman have been sacked.
With that in mind, Sports Mole takes a closer look at why Erik ten Hag was sacked, and where his dismissal leaves the club.
Defensively weak
Manchester United began life under the former Ajax boss poorly, losing 2-1 against Brighton & Hove Albion before being humiliated 4-0 against Brentford in their first two games of 2022-23.
To Ten Hag's credit, he quickly recognised that his side were incapable of playing an expansive brand of football without being exposed defensively and consequently resorted to a risk-averse playstyle.
This involved relying on counter-attacking moments to generate chances, just as his predecessor Ole Gunnar Solskjaer's side did too.
However, United's fundamental defensive weaknesses remained in spite of the change of playstyle, with the team losing 6-3 against Manchester City and 7-0 against fierce rivals Liverpool in 2022-23.
The likes of Lisandro Martinez are excellent on the ball, but his poor physical level meant he often lost out in duels with opposition strikers when deployed at centre-back.
United's midfield also often lacked athleticism, with Casemiro and Christian Eriksen featuring regularly and finding some success in Ten Hag's first campaign, but ultimately coming up short in games against teams with superior athletes in the middle third.
In 2023-24, United were calamitous defensively, with the team posting defensive stats that would be more fitting for a side stuck in a relegation battle.
For instance, United conceded the third most xG per game, as well as facing the second most shots against over the course of the season, with only Sheffield United facing more than the Red Devils' 660 shots.
These figures were exacerbated by Ten Hag's decision to have his midfield and attack aggressively man-mark opponents, while also instructing his defence to drop deeper than the rest of the XI.
This created a gulf in the middle of the pitch and out wide, space that was routinely exploited by technically and athletically superior teams.
However, the Dutchman's side only conceded 57 goals when stats suggest they should have conceded closer to 70 times.
This would suggest that United's eighth-placed finish, which was the worst in the club's Premier League history, was fortunate and the situation could have been worse had their defensive vulnerabilities been punished.
Interestingly, United have faced 103 shots this season and that is the Premier League's sixth best record so far, but they have still conceded the seventh most xG in the top flight.
The fact that United have conceded two or more goals in 47 of Erik ten Hag's 127 games in charge ultimately highlights the frailty of his team.
Offensively weak
Another reason why Erik ten Hag has been sacked is that his side have been poor offensively this term, with the club only scoring eight times in the Premier League, the third fewest of the 20 sides in the division.
Admittedly, United have missed the joint most big chances alongside Tottenham Hotspur, but this is not the first time that the club have been concerning from an offensive perspective.
In 2023-24, the Red Devils created 56.5 xG and only scored 57 times in the league, the 10th highest and ninth highest figures respectively.
Forwards such as Marcus Rashford, who managed to score 17 goals and produce five assists in 35 Premier League games in 2022-23, has only scored eight times and registered three assists in his last 42 league appearances.
Others like Bruno Fernandes have done well in terms of numbers, and the midfielder has scored 18 times and assisted on 18 occasions in the top flight since Ten Hag's arrival, but the Portuguese has often been criticised for repeatedly losing possession and contributing to chaotic matches.
The former Red Devils boss struggled to implement a consistent style of play at United, with the Dutchman having insisted that he did not have the players at his disposal to do so despite spending £600m during his tenure.
Former Ajax winger Antony was signed in August 2022 for a fee in excess of £80m, but arguably became emblematic of Ten Hag's failings, scoring just five times in the Premier League and only producing three assists to date.
Forwards Rasmus Hojlund and Joshua Zirkzee have also struggled to showcase their best level, and highlight Manchester United's poor squad building under the Dutchman given both were signed for significant fees and are arguably competing for the same spot in the XI.
Where does Ten Hag's dismissal leave the club?
The club announced that Ruud van Nistelrooy will take charge of United on an interim basis, with the team set to take on Leicester City at Old Trafford on Wednesday in the fourth round of the EFL Cup.
Van Nistelrooy's first Premier League match will be against Chelsea at home on Sunday, but he is unlikely to be given the job full time regardless of how he fares considering United announced they have begun the search for a permanent head coach.
Thomas Tuchel was reportedly of interest to officials at Old Trafford, but the German was recently named manager of the England national team.
Others such as Gareth Southgate have been routinely linked with the club, but his failure to win either Euro 2020 or Euro 2024 despite the talent that was at his disposal is a mark against his record.
Former Barcelona boss Xavi has also been linked,, and to his credit, he can point to the fact he has won a league title against Carlo Ancelotti's Real Madrid amidst off-field strife.
Perhaps Jim Ratcliffe would be wise to appoint a younger manager such as Sporting Lisbon's Ruben Amorim or Stuttgart's Sebastian Hoeness, who have both found success at their respective clubs.
However, Van Nistelrooy will hope to improve the immediate situation at United, help the club escape the bottom half and push towards the Premier League's European qualification spots.