Real Madrid have a problem. Manchester United have one, too. They might be two of the biggest clubs in world football, but when there is a dearth of world-class coaches capable of making good of a bad situation, not even money and history can generate a solution out of thin air.
Having overseen a disastrous run of five defeats in seven games -- the most recent being a humiliating 5-1 defeat against Barcelona at the Camp Nou -- Julen Lopetegui's brief reign as head coach at the Santiago Bernabeu has finally, perhaps mercifully, come to an end. Such form would put any manager under pressure, but with that kind of run at Real Madrid, it became obvious that it was time for Lopetegui to clear his desk and plan for a holiday.
At Old Trafford, Jose Mourinho has weathered the storm that threatened to engulf him during a run of four games without a win in late September and early October, but he is not out of the woods yet in terms of his job security at United. The club sit eighth in the Premier League after Sunday's 2-1 win at home to Everton, nine points adrift of leaders Liverpool, and there remains a sense of Mourinho's team limping along, doing just enough to keep the coach in a job.
That Mourinho continues to hold on and that Real are promoting B-team coach Santiago Solari to first-team manager in the interim is a testament to the lack of alternatives available to both clubs.
United's owners, the Glazer family, are determined to give Mourinho the time to oversee a revival and surge into the top four, but sources have told ESPN FC that this position is largely influenced by the barren field of potential replacements.
As for Real Madrid, they will have to find a replacement who can handle the mammoth challenge of managing a failing super club with a dressing room full of big personalities who are under-performing. The smart money is on Real turning to Antonio Conte, out of work since leaving Chelsea in the summer, as their next permanent coach. But while the former Juventus and Italy coach possesses a glittering CV, with domestic titles in Italy and England, there is no escaping the fact that he was sacked in his previous job at Stamford Bridge.
Who's out there, right now, who can save Manchester United and Real Madrid?
The managerial superstars -- those whose careers are unblemished by failure or the ignominy of the sack -- are out of reach. Manchester City have their guy in Pep Guardiola, Liverpool are challenging again under Jurgen Klopp, and Diego Simeone has resisted countless opportunities to leave Atletico Madrid.
Massimiliano Allegri is perhaps the next name on that stellar list, having won five Serie A titles with AC Milan and Juventus, as well as guiding Juve to two Champions League finals. Real and United might fancy their chances of luring the Italian next summer, but there is no chance of the 51-year-old leaving Turin midseason.
Carlo Ancelotti would have been the perfect option for Real and United, had he been available, but the Italian returned to work with Napoli in the summer after his unsuccessful stint at Bayern Munich.
Chelsea have recruited well with Maurizio Sarri, Arsenal have hired a proven winner in Unai Emery, and Paris Saint-Germain have given Thomas Tuchel the chance to show Bayern what they missed when choosing to ignore his credentials by appointing Niko Kovac as Jupp Heynckes' successor earlier this year.
Tottenham manager Mauricio Pochettino is regarded by many as the next big thing, but he is tied to a long-term contract at Spurs, and his lack of silverware as a coach means that a club of Real or United's stature would be taking a gamble on his potential, rather than his track record.
Zidane, having left Real in May, is unlikely to return to the Bernabeu now that Lopetegui's gone, but he might be an option for United. Once all of the above have been ruled out as unattainable, certainly in the here and now, who is left for the big clubs to choose?
Julian Nagelsmann, the Hoffenheim coach, has agreed to move to RB Leipzig next summer, so the 31-year-old is another who is out of reach.
How about an English coach? There must be at least one Englishman capable of managing a super club. Perhaps Gareth Southgate and Eddie Howe have what it takes, but don't expect United or Real to go down that route. To manage the biggest clubs, a coach must either possess a gilt-edged CV or have such dazzling potential that he cannot be ignored.
But right now, the managers who tick those boxes are in big jobs, so even Real Madrid and Manchester United will have to settle for second best if they choose to appoint a new man in the dugout before the season ends -- a season that could easily slip away from both clubs.