After just two victories in seven matches, fractures have emerged in Xabi Alonso's Madrid project, with some Spanish media reporting a defeat against City could lead to a premature dismissal.
So often this season Madrid have underwhelmed but been rescued by Mbappe's lethal brilliance, scoring 25 goals in 21 games to lead the scoring charts both in Spain and in the Champions League.
Pep Guardiola's City are spearheaded by Norwegian international Haaland, who has 20 goals in 20 games across all competitions and, along with Bayern Munich's Harry Kane, is Mbappe's only rival as the standout star of the current season.
The pair have also been drawn against each other at next summer's World Cup in the United States, with Mbappe's France to face Haaland's Norway on June 26th in Foxborough, Massachusetts.
The first chapter of that battle will be played out at the Bernabeu, where former Barcelona coach Guardiola would relish being able to add to Madrid's misery.
This season City are structured around Haaland, playing to the forward's strengths and aiming for the majority of their moves to end with the ball at his feet in front of goal.
What structure Alonso tried to impart at Madrid has crumbled away amid a tussle for power with the players, although Mbappe's quality has made him their key figure.
"The team is a flat, uninspired group clustered around Mbappe, whose goals merely mask the crisis," wrote Spanish newspaper AS on Sunday after a 2-0 home defeat by Celta Vigo.
"If he takes a day off, there's no alternative."
Mbappe has been Madrid's one constant this season, thriving when the team was doing well during a run of 13 wins from 14 matches, but also in recent weeks amid their struggles.
After a slow start to life in Spain following his move from Paris Saint-Germain in the summer of 2024, Mbappe found his top gear in the second half of last season.
In 2025, he scored 55 goals for his club, four short of the 2013 record of 59 set by Cristiano Ronaldo, his childhood idol and Real Madrid's all-time top goalscorer.
Splintering Madrid
Mbappe has emerged as a unifying force at Madrid, even as the team splinters around him.
Alonso arrived aiming to impose himself as a coach cut from a different mould than Carlo Ancelotti and Zinedine Zidane before him, considered excellent man-managers, but with less of a tactical and technical focus.
With Mbappe as his only untouchable outfielder, Alonso started the season by rotating Vinicius Junior with Rodrygo Goes and Dani Carvajal with Trent Alexander-Arnold, constantly shuffling his pack.
Jude Bellingham was sidelined after shoulder surgery and Arda Guler was thriving in midfield.
The team ground out results but discontent among some star players grew, coming to a head with Vinicius' fit of rage after being substituted in the Clasico in October, which Madrid won.
Bellingham's return from injury further forced Alonso's hand over selection, along with Fede Valverde's reticence to play out of position at right-back.
A string of away matches, in part because the club were hosting an NFL game at the Bernabeu, contributed to their recent slump as the signs of Alonso's ideas about pressing have diminished and the big-name players start every match.
After a 1-1 draw at Girona at the end of November Mbappe called on the team to "show who we are" and "change this dynamic".
"It's not just about goals for Kylian... but he does other hugely fundamental things like leadership, influence, helping his team-mates, and that's so important day to day," said Alonso, appreciating the calls for unity from Mbappe.
Madrid thrashed Athletic Bilbao 3-0 last week, with the result an outlier in their recent form, with AS claiming the players were particularly motivated by the promise of two days off for a victory.
Those days, taken ahead of the defeat by Celta, may have contributed towards the defeat, which could have finished in a draw if Mbappe's lob had fallen under the crossbar rather than just over it, with the Galicians leading by a single goal.
It was a question of millimetres, but would again have been a case of Mbappe papering over the deepening cracks. And yet against the might of City and Haaland, in the eye of the storm, for Alonso even that would do.