Complex sentence: The 2003--2004 season, with Maurizio Pellegrino as coach, ended in a lacklustre relegation after playoffs to Vis Pesaro, was the last for the club, that declared bankruptcy in the summer.
Split into simpler sentences: The 2003--2004 season, with Maurizio Pellegrino as coach, ended in a lackluster relegation for the club after the playoffs to Vis Pesaro. It would be the last for the club, which declared bankruptcy in the summer.