In 2001, Ipswich Town signed him for £4.5 million,[1] which was the highest transfer fee paid by the club, until the acquisition of Omari Hutchinson[2] in 2024.

In 2004, he started for the club in both legs of the 2004 Coppa Italia Final against Juventus FC and played the matches in the 2005 UEFA Intertoto Cup, when Lazio went out to Olympique de Marseille in the semi-finals.

He returned to Lazio for the 2006–07 campaign, but did not play a single match, being excluded from the roster for the whole season.

[9] A few days before the last game of Serie A, his contract was mutually terminated, following the club's relegation a few weeks before.

After divorcing his ex-wife Silvia, Sereni was accused of having raped their daughter during a 2009 holiday on Sardinia's Costa Smeralda.