Kaká's brilliant display where he single-handedly lifted AC Milan over a resilient Celtic, was offset by the frustration experienced by Ronaldinho, as a surprisingly dour Barcelona team was tactically shutdown by a well-coached Liverpool club.

To be fair to Ronaldinho, he didn't play that poorly on the night, and only the post prevented him from scoring a goal that would likely have put Barcelona into the quarterfinal round. However, his frustration on the night and over the two legs, during which he was effectively shackled by the Liverpool defense, could be measured by the uncharacteristic kick he aimed at Liverpool defender Jamie Carragher's legs when the ball had gone well clear.

It was the culmination of a rough couple of weeks for Ronaldinho, who has been universally accepted as the finest player in the world for the past couple of years. For the first time since the rather controversial end to his time at PSG, prior to his move to Spain, Ronaldinho received heavy public criticism about his physical conditioning after the defeat in the first leg to Liverpool.

A picture of a shirtless Ronaldinho after the game was contrasted with a picture taken a couple of years ago. The fact that Ronaldinho supposedly looked slimmer a few days later when he took of his shirt after a La Liga match, led some of his supporters to claim the "fat" pictures were doctored and the work of an anti-Barcelona faction. Cue various statements from Ronaldinho himself denying he was fat and his teammates who memorably defended Ronaldinho's right to eat.

The fact is, Ronaldinho has been in midst of a dip in form by his standards ever since the tail end of last season, where he failed to produce in either the Champions League final or the World Cup. The common wisdom was that the jocular Brazilian would have much to prove this season and his 17 goals in La Liga play would seem to attest to that.

However, those who have watched Ronaldinho extensively the past few years, would have to admit that at present, he's not close to being the same player of a few seasons ago. Granted, it's impossible for a player to maintain that level consistently over such a long duration, but Ronaldinho's not helping his cause with his seemingly lax attitude to physical conditioning.

Is he fat? No -- but he's definitely much heavier than he used to be. Some of that was deliberate by design as he sought to put on more muscle to withstand the rigors and physicality of European soccer, but there's no doubt his laissez-faire approach to training (rumor has it he shows up only when he feels like it) has caused his physique to slide the past couple of seasons. He obviously still has the skills, but it's clear he's lost that extra gear he used to possess which left every defender in his wake.

That said, even a heavier Ronaldinho remains one of the best, if not the best, players in the world. But these days, that title is no longer a given and he's being given a serious run for his money by Kaká and Manchester United's brilliant Portuguese winger Cristiano Ronaldo, who has taken his game to another level this season.

For fans of Ronaldinho there has to be concern that he lacks the training discipline to regain peak physical form -- I'd hate to see him follow in the footsteps of another Brazilian, Ronaldo, whose decline in recent years owes much to a similar disinclination to train or adhere to physical conditioning. True, Ronaldo was never the same player after a series of brutal knee injuries, but he didn't help his cause with his work ethic and dietary habits.

For Brazil, the safer long-term bet for sustained greatness at this point might be Kaká, who may lack the outrageous flair, skill and audacity that Ronaldinho can produce, but is a brilliant player in his own right. More reassuringly for Brazil, Kaká is far more serious and dedicated to his profession than the playful Ronaldinho.