Kaka's magic threatens the advance of Celtic

South American prodigies tend to spring from tales of rags to riches with young hopefuls - like Pele, Maradona and Ronaldo - growing up in tough, urban environments and playing keepy-uppy along dirty, crime-ridden alleys.

South American prodigies tend to spring from tales of rags to riches with young hopefuls - like Pele, Maradona and Ronaldo - growing up in tough, urban environments and playing keepy-uppy along dirty, crime-ridden alleys.

Milan's 22-year-old Brazilian Kaka has emerged from a different mould, though. His upbringing in the prosperous capital city, Brasilia, was a world away from the sprawling favelas that spawn generation after generation of samba footballers. But his relatively privileged upbringing has not stopped Kaka from being regarded as the outstanding Brazilian prospect. In fact, he is already regarded as a key member of the national side.

Kaka, or Ricardo Izecson Santos Leite to give him his full title, did not take long to catch the eye when he began playing for São Paulo. Playing as a deep-lying forward or attacking midfielder, he scored 22 goals in 56 league games and a host of European clubs began to pay attention. Milan were confident he was their man and were prepared to allow him to stay another year in Brazil only to be forced into pre-emptive action 14 months ago when Chelsea started sniffing around.

There have been no regrets for the Rossoneri because Kaka was an immediate revelation, replacing Rui Costa as the first-choice playmaker and showing vision and ability beyond his years. His performances left some of football's most famous names raving. Pele called him "already one of the best players in the world", while the usually understated Zico has eulogised him as "without a doubt Brazil's finest discovery" and compared him to Brazil's legendary captain of the 1980s, Socrates.

With Kaka taking Serie A by storm, Milan went on to win the league and should really have held on to the Champions' League trophy as well. Kaka scored one of the outstanding goals of the Champions' League in a 4-1 thrashing of Deportivo La Coruña in the quarter-final, first leg, controlling a cross from Cafu on his knee while on the run, and then lashing a volley low into the corner.

In one of those inexplicable occurrences that makes football such an unpredictable game, Milan lost the return leg 4-0 and were out, leaving only Kaka's goal as the abiding memory of their tournament.

The 6ft midfielder, whose boyish good looks have made him a favourite with female fans - and sponsors - in Italy, has struggled to maintain the same level of performance this season. But, ominously for Celtic, who face Milan at San Siro in Group F of the Champions' League tonight, he appears to be returning to something near his peak. A new one-year contract extension was announced earlier this month tying him to Milan until 2009 and he responded by scoring his first goal of the season. He has a natural arrogance, too, claiming that "it would be a miracle" if Celtic go through from the group stages and Milan do not.

Kaka brushed off criticism of his displays in pre-season, saying: "Criticism is part of the game, as is praise but it did annoy me because we were playing friendlies and not at a high level. I accept the criticism but I had a good and hard training period which will bear fruit during the season.

"I want to win everything at Milan. I arrived a year ago and I wanted to demonstrate at all costs that I could play in Italy. Now, a wonderful year later, I have shown that."

He should feel even more so after Milan's decision to sign his younger brother, Digao, on loan for the season. The 19-year-old defender, also a product of São Paulo, will play for Milan's reserve side after the club reached an agreement with Sampdoria.

Kaka's arrival at Milan also heralded the end of Rivaldo's spell there and he has gone on to replace him at international level, too. He is also a different sort of player. While Rivaldo was all trickery and skill, Kaka has athleticism and power too. Celtic need to be particularly wary of his late runs into the box that are so difficult to defend against.