Juan Roman Riquelme was sought by Corinthians two years ago when they were building a team to try to win the Libertadores Cup for the first time in their centenary year.
Now Riquelme, who said he did not want to leave Boca Juniors, stands in the way of Corinthians who have at last reached their first final clash with the Argentine six times South American champions.
Boca are at home in Wednesday's first leg at La Bombonera in Buenos Aires as they bid to equal the record seven victories of fellow Argentine side Independiente.
"There are no favourites," Corinthians coach Tite told reporters almost defiantly outside the team's hotel in Buenos Aires on Tuesday.
"You're never going to be relaxed in a final, because of what you're playing for, because of the expectations, the importance.
"A magic formula? We have to do what we've been doing, play the same way at home and away, Corinthians are a team more than individuals," added Tite of his side whose strong defence have conceded only three goals in 12 games in the tournament.
Boca's magic formula could be said to be Riquelme, the best player in the Argentine domestic game and the key player in their progress to the final.
He earned respect in Brazil for his Libertadores exploits, primarily against Brazilian teams and especially in the away legs in Brazil.
Boca have won four of their titles this century and Riquelme was a part of three, having missed the 2003 victory over Santos after moving to Barcelona.
In 2000, the year Boca went on to beat Real Madrid in the Intercontinental Cup final, Riquelme helped them beat Palmeiras, Corinthians' Sao Paulo neighbours, on penalties and the following year they beat Cruz Azul of Mexico, also in a shootout.
In 2007, Riquelme scored both away goals and three altogether in the tie as Boca romped past Brazil's Gremio 5-0 on aggregate.
Two of Boca's defenders are also veterans of previous finals including left-back Clemente Rodriguez who has won the trophy three times.
Centre-back Rolando Schiavi, who is 39, played for the 2003 winners and also helped Juan Sebastian Veron's Estudiantes lift the trophy in 2009 before returning to Boca last year.comments