Biagini then played five seasons with RCD Mallorca where, safe for his first year where he scored a career-best 11 goals (also helping the team to the final of the 1998–99 UEFA Cup Winners' Cup by scoring the 1–0 winner against Chelsea in the last-four's second leg, in a 2–1 aggregate victory), he would be very scarcely used due to several injury problems, also serving a six-month loan to England's Portsmouth in the First Division, where he found the net against Millwall and Wimbledon.