On 31 January 2006, to the surprise of most fans, D'Alessandro joined English Premier League club Portsmouth on loan for the remainder of the season. His main objective with his new club was to blend in with new teammates and help his club to avoid relegation. On Easter Monday, 17 April, he scored his first goal in English football – a contender for goal of the season – in Portsmouth's 2–1 defeat away to Charlton Athletic.
