Blackburn were relegated to the First Division in Jansen's first season, but he was the star of the team which won promotion back to the Premier League in the 2000–01 season, finishing as the league's second top scorer, after Fulham's Louis Saha, with 23 goals. He continued to impress in the following season, scoring the first goal in Blackburn's 2–1 League Cup final victory against Tottenham Hotspur in 2002. His good form led to an England call-up for the friendly game against Paraguay. However, he missed out on what would be his only International football match for his nation due to a stomach bug.