The greatest fixture in the history of football, Real Madrid vs. Barcelona, is balanced on a knife edge.

After 119 years of playing Clasicos, making up 246 matches, the record stands: Madrid 98 wins, Barca 96. They've divvied up the goals almost equally -- Madrid 410, Barcelona 401 -- during all those thrills and spills it's divided the world, winning new fans on every continent, while the astronomical viewing figures have grown higher than ever before. It has literally become a phenomenon.

Sunday's Clasico at Camp Nou will draw on passion, skill, ego, anger, revenge, creative invention, risk taking, chutzpah, fear, loathing, desperation, arrogance and ambition. The perfect cocktail. And yet there's a very strong case that it's not even the most important game either side will play this week -- let alone this season.

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Even with 40 goals scored in 12 meetings, Barcelona vs. Dynamo Kiev isn't a classic fixture. Far from it. Ditto Shakhtar Donetsk vs. Real Madrid. Even though there's an average of more than four goals every time they meet, it's never been a draw and the wins are split exactly evenly, this is not -- I repeat not -- the kind of fixture Florentino Perez had in mind when he tried to drive a coach and horses through European football with his ill-devised, badly presented, furiously rejected European Super League.

Yet the harsh fact is that when the Ukrainian big guns go toe to toe with Spain's big dogs in the week preceding the Clasico, each match is arguably more crucial to LaLiga's dominant duopoly than when they meet on Sunday. That's true even with the possibility of Madrid putting a five-point gap on Barcelona by winning their third straight LaLiga Clasico for only the first time in 43 years.

You'll never get proud, fiercely partisan, irrepressible Joan Laporta, Barcelona's talismanic if beleaguered president to admit it, but if by next Monday the Catalans have defeated Dynamo Kiev 1-0 in the 95th minute with a goal that should have been ruled offside but wasn't while the Camp Nou bayed its dissatisfaction and then, humiliatingly, lost 0-3 to Madrid, it will have been a good week for him, the club and their utterly atrocious financial situation. That's because Ronald Koeman's team has been dismantled 6-0 on aggregate over their two previous Champions League Group E games against Bayern Munich and Benfica, and defeat at home to the Ukrainian champions would, effectively if not arithmetically, mean that Barcelona wouldn't be reaching the knockout stages of this competition for the first time in more than two decades.

Embarrassing, yes. A cue for huge criticism and opprobrium from fans and media -- and probably the trigger for Koeman's dismissal. But above all, a complete financial nightmare.

The difference in what a club like Barcelona will earn from UEFA if falls flat on its face before Christmas, instead of punching onwards even to the quarterfinals, never mind the final four or the showpiece in St. Petersburg itself, is, conservatively, €70 million to €80m.

Given Barcelona's debt situation, which is nudging €1.5 billion, that's an absolutely intolerable scenario. It would be sufficient to make defeat at home to Mircea Lucescu's team on Wednesday, pound for pound, the worst result in Barcelona's 122-year history (their birthday falls at the end of November).

The five-time Champions League winners improved at the weekend in beating Valencia 3-1. Not nearly enough to suggest that beating Dynamo on Wednesday is a calm prospect, but with Ansu Fati bossing the match, at just 18 and after a year out injured, and Koeman ordered by the overly patient Laporta to dump the horrendously misjudged 3-5-2 formation so that Barcelona returned to their recognised 4-3-3, they produced their best work of the season.

So, perhaps they dispense with the Ukrainian threat and prepare to welcome Madrid with muscles bulging, teeth bared and fragile confidence shored up. Perhaps.

But should they lose midweek, they'd be rock bottom of the group, second best in the head to head with each rival, and facing a horrible trip to Kiev. There would still be nine points in play, but the elimination-confirmation fixtures thereafter would be Benfica at Camp Nou and all-conquering Bayern in Munich.

Real Madrid are in a dilemma of a different nature. Three wins and two semifinals in the past seven years still awards them huge Champions League pedigree. And although it was last-minute, smash-and-grab stuff, the fact remains that Los Blancos beat Italy's champions to make sure that they're off the mark in this year's competition.

However, a multitude of factors make their trip to Donetsk a competitor with the Clasico in terms of importance.

Madrid's horror-show home defeat to Sheriff, a 24-year-old club that has a 12,000-capacity stadium and operates out of a breakaway state between Moldova and Ukraine, looked and felt like an anomaly. Thirty shots at goal, 11 on target, a flurry of corners but defeat to a team that produced its wonder-winner from a Luxembourg international. It sounds unfeasible.

However, there's a pattern. This club whose president was the schemer-in-chief for a Super League in which there's no relegation for founding members, which resembles a closed shop and which money making is at least as important as trophy lifting, lost comprehensively home and away to Shakhtar last season.

Teams that dare, teams that counterattack superbly, teams that exploit the lack of outright pace in Madrid's midfield can win big dividends. In the first version of this fixture in Donetsk last season, Zinedine Zidane's side found the constant, aggressive, hungry pace of the Shakhtar harassing and counterattacking too much for them.

Now under Carlo Ancelotti's control, Madrid don't want to approach Sunday's Clasico having suffered a third straight defeat. Questioned on Monday as to why it is Los Blancos seem to have a dip at this time of year in recent seasons, Ancelotti answered: "I honestly don't know the reason. Right now it's normal that teams aren't at full energy and fitness. The international breaks do affect clubs. But this isn't the most important period of the season -- that comes in April and May when the finals are played."

Yes, OK, Carlo. But Madrid's president isn't the kind of man to see a defeat in Donetsk, for the second year running, be added to losses against Sheriff and Espanyol. A hat trick of defeats is unpalatable for Madrid at the best of times, but to relative minnows like those teams, it would seem disastrous to Perez.

Because Madrid have been far, far shrewder in managing their finances -- noticeably less frivolous and less mired in failure than former president Josep Bartomeu's Barcelona -- doesn't mean that the pandemic hasn't badly hurt them financially. It's crucial that the 13-time winners negotiate the group stage.

But Perez is a guy for whom dignity, ego, bragging and sneering rights are very important indeed. For him to think that clubs like Bayern and Paris Saint-Germain, who weren't part of the failed Super League project and who've firmed up their European power as a result, or to think that UEFA president Aleksander Ceferin, are all laughing up their sleeves at him if Madrid stumble in Ukraine -- well, Madrid's president takes that kind of embarrassment extremely badly.

Even in testing times, Barcelona and Madrid are such extraordinary clubs that they may arrive at the Camp Nou on Sunday having given their Ukranian rivals bloody noses and thereby relieved some of the intense European pressure they're definitely under right now. But the alternative scenario is that Spain's 247th Clasico is potentially a job saver for two great men of modern European football, Koeman and Ancelotti, and a scenario in which each team desperately needs a win-at-any-cost performance because the word "crisis" has begun to be bandied about. Not by the media or fans, but by Laporta and Perez, the men who control the futures of Messrs Koeman and Ancelotti.