Leinster's first season in the newly formed Celtic League ended in success as the Lions were crowned the inaugural champions, beating rivals Munster Rugby in the 2001–02 final. In 2002–03, they became only the third team in the history of the European Cup to win all their games in pool play. They also went one step further in the playoffs than the previous season by reaching the semi-finals (for the first time since 1995–96), but lost at home against French side Perpignan, which was accompanied by an unsuccessful season in the Celtic League. The 2003–04 season also ended in disappointment as Leinster slumped to their worst ever league performance and failed to qualify from their European Cup group.