The two teams who meet at the Bernabeu on Wednesday night currently occupy vastly differing spheres of the football world. Real Madrid, on the up with a host of new superstars currently plying their trade in Spain, host AC Milan, a side who have fallen from grace spectacularly since their domination of Champions League finals a few years ago.
No-one has been more affected by the situation of the two European giants than Kaka, who is facing his old side for the first time. Sold for £56.5 million this summer, the Brazilian midfielder was the heartbeat of Milan's attacking play; a lynchpin the club could turn to in troubled times. Now, in the absence of injured £80 million man Cristiano Ronaldo, he could be the man to drive the stake into the hearts of those he once loved.
Milan are a club with a vast and impressive history. Whether it's the 5-0 trouncing of Real Madrid in 1989, the Fabio Capello-inspired 4-0 demolition of Johan Cruyff's Barcelona in the 1994 Champions League final, or their most recent successes with Kaka in the ranks - when they reached three European finals in five years - they had become one of Europe's most feared clubs. But not now.
Now, the Rossoneri are viewed as a wounded beast; a side shorn of their former stars and reliant on a group of ageing veterans to keep them afloat. Unable to resist the offers from their more wealthy rivals, Milan appear ripe for the picking and, after cashing in on Kaka, would now do well to hold onto their other Brazilian star, Pato, in the midst of an apparent financial crisis.
In truth, the need to rebuild their squad has been painfully apparent for a few years. Pato aside, Milan's transfer business has not been good and they have really only splashed out on one player, Alberto Gilardino, who has since left the club after failing to impress. The rest of the acquisitions have either been the wrong side of 30, not up to the expected standard, or calculated risks on former superstars who others wouldn't touch - with Ronaldinho and Ronaldo the two that spring to mind.
But it is of their own making. Ignoring the talents of France's young hope Yoann Gourcuff, a ready-made replacement for Kaka who they sold to Bordeaux, and failing to up their £15 million bid for Sevilla striker Luis Fabiano by a paltry £2 million, Milan have chosen their path and are, instead, left with attacking options such as Clarence Seedorf, 33, and Filippo Inzaghi, 36. Only Livorno, anchored to the bottom of Serie A, have scored fewer league goals than Milan this season.
Now the club are under more pressure than ever. In recent years, results on the pitch began to suggest that their transfer philosophy was not working - as they finished outside the Champions League places in 2007-08 - but nothing has been addressed and further defeats to FC Zurich and a 4-0 drubbing at the hands of Inter only serve to highlight their decline this season.
Indeed, Milan have 15,622 fewer season ticket-holders than last season, hinting that the situation at the club is beginning to effect their loyal fans too. With the Scudetto almost out of reach already, Europe is the only place they can rescue their season and with Real Madrid seemingly blazing a trail through the competition, it looks a tough ask to even make it out of the group stages if they slip up again.
In contrast, Madrid are a team on the up. Unlike Milan's Silvio Berlusconi, Bernabeu chief Florentino Perez has ploughed millions into the club to revive their hopes, both domestically and in Europe, claiming that they "have an obligation to win everything every year."
Madrid's transfer policy targeted the best young players in the world and, although they were helped by some unprecedented spending power, they have shown their ambition to head back to the top of the world game. Perez's second galacticos era brought in the likes of Ronaldo, Kaka, Karim Benzema and Xabi Alonso and removed some underperforming stars, but it was motivated by a desire to bring back the European trophy for the first time in eight years - as the last time they won it was when Zinedine Zidane, Fernando Hierro and Luis Figo were still playing for the club in 2002.
Real have proven that their revival is in full swing with a goal glut that has seen them top the scoring charts both in La Liga and in Europe, even if their pursuit of the world's best talent is somewhat questionable morally. They may suffer from the occasional lapse in defence, but Madrid carry the type of attacking threat that those at the San Siro will remember fondly from their past glories.
With Madrid's ambition clear for all to see, Kaka's decision to swap the San Siro for Spain this summer made footballing sense and that will hurt Milan. With the Italian giants currently on such a decline that missing out on the Champions League next season looks like a distinct possibility, it may hurt them even more that their fate in the group stages could almost be sealed by back-to-back defeats against a club with similar aspirations, who also boast one of their former legends.
Milan's vice-president Adriano Galliani has put on a brave face before the game: "It is 'The Match' - the two teams have won 16 European Cups between them. And we certainly don't travel to Madrid feeling psychological subjection," he said. Thoughts of Milan's past glories may well be clouding judgements at the San Siro, but a rejuvenated Madrid could bring them sharply into focus on Wednesday night.