Remember when Manchester was billed as the capital of football? When United and City shared four Premier League titles in successive seasons between 2011 and 2014, it seemed as though the city's dream was close to coming true. If anyone had predicted in those heady days three years ago that Pep Guardiola and Jose Mourinho would soon be in charge at the Etihad and Old Trafford respectively, the assumption would have been that the Mancunian clubs' domination was about to be entrenched.
It has not worked out that way.
Under Mourinho, United are still undergoing a rebuilding process as they try to adjust to life after Sir Alex Ferguson. After the euphoria of signing the game's most sought-after manager and spending more than £150 million in the transfer market before the season started, City are in crisis.
The 4-0 defeat by Everton at Goodison caused City to drop out of the top four. They have lost four of their last eight games. United, in sixth place, are just two points behind their neighbours.
On Saturday, City face Tottenham Hotspur in a match that could determine the direction of both teams' seasons. Spurs are buoyant. They have won their last six games and are emerging as the most serious challengers to Chelsea for the title. They've also conceded just 14 goals in the league and go to the Etihad brimming with confidence.
It is the last thing Guardiola needs. The 45-year-old is not getting his message across to the team. There is no dressing-room revolt at City but doubt has infected the players. The Catalan was aware that the problem was growing after the defeats by Chelsea and Leicester City in December and countered it by allowing his assistants, Domenec Torrent and Mikel Arteta, to take a more prominent role. Arteta addressed the team for the Arsenal game and helped rouse the side to a 2-1 comeback victory over his former club.
It looked as if the wobble was over until the rout at Goodison proved the malaise runs far deeper. Guardiola, so often an animated force of nature on the sidelines, looked spent. The City manager is rarely short of ideas but he seemed temporarily bereft.
His team has problems across the pitch. The most obvious issues are at goalkeeper, where Claudio Bravo has been deeply unconvincing, and the defence, which is prone to errors. But Guardiola's biggest conundrum is in midfield. Injuries deprived City of Fernando and Fernandinho against Everton but the combination of Pablo Zabaleta and Yaya Toure in the middle of the park surrendered the impetus to the home team.
Guardiola has plenty of weapons at his disposal on the front line but behind the attacking quartet of Raheem Sterling, Kevin De Bruyne, David Silva and Sergio Aguero, there are huge gaps for opponents to exploit. Tottenham, with their strong defence and thrusting, relentless midfield, will find plenty of room to play at the Etihad.
How will Guardiola fix things? With difficulty. The former Barcelona coach tends to isolate himself when pondering big decisions and before the Spurs game, he has a lot of thinking to do. For example, it may cross his mind that Txiki Begiristain should have done better.
Begiristain was director of football at the Camp Nou during Guardiola's tenure and now occupies the same position at the Etihad. The 52-year-old joined City five years ago and was meant to prepare the club for Guardiola's arrival. The manager might reflect that he was handed an unbalanced and ageing squad, especially in defence; Begiristain has developed a habit of overpaying for targets who prove ineffective. Eliaquim Mangala, who is now on loan at Valencia, cost £40 million. Nicolas Otamendi and John Stones look nothing like £80 million's worth of centre-backs should. The lack of adequate, adaptable midfielders must also frustrate the manager.
Missing out on the Champions League next season would be unthinkable at the Etihad. Guardiola was brought to Manchester with the intention of making City a significant European force and lifting the club's global profile. The English side face Monaco in the knockout round of the Champions League but even the most optimistic City fans would struggle to imagine them qualifying for next season's tournament by winning the competition. Dropping out of the top four domestically would set back the Guardiola "project" considerably.
Cynics underplay the Catalan's achievements at Barcelona and Bayern Munich by suggesting Guardiola was gifted strong clubs in weak leagues. It is nonsense to dismiss his talents so glibly, yet it's also clear that the next few weeks present the biggest test in his management career so far.
After City's bright start to the season -- they won the first six games -- too much was expected of the team. However, the minimum requirement is a top-four finish. Missing out on next year's Champions League would hurt Guardiola's reputation but focus minds at the Etihad on the need for better recruitment and sharper scouting.
The danger for Manchester is that next season it will be the capital of the Europa League. That is unthinkable across the metropolis. If Guardiola can't fix things against Spurs, that nightmare scenario will move one step nearer reality.