Carboni formed an efficient full back partnership with Jocelyn Angloma (born in the same year) in his first years with the "Che", eventually helping the team to two national championships – the French had already left the club in the 2003–04 conquest – and five other trophies. He also helped Valencia to the 2000–01 UEFA Champions League final against FC Bayern Munich, but missed his penalty in an eventual shootout loss; during the first 120 minutes, he also committed the penalty that led to the Stefan Effenberg 1–1 equaliser.