He made his professional debut on 31 March 1999 against Slovakian Miroslav Dzurenda in Worb, Switzerland. The 22-year-old Seferi won the fight by a knockout in the first round. his first defeat came on 16 June 2001 to Ukrainian Kostyantyn Okhrey, with Seferi being unable to continue in the 4th round due to a rib injury. Of his first 10 wins in 6 round bouts, all were won by knockouts in the first 4 rounds, with 6 knockouts coming in the opening rounds.