The 2005-06 campaign delivered a vital return to the top-flight for Sparta Rotterdam, as De Kasteelheren secured a hard-fought 14th-place finish in the Eredivisie after a three-year absence. Leading the attack was the forward Jason Oost, whose 8 crucial goals proved decisive in a season built on a strong post-promotion start that defied relegation predictions. It was a year of successful consolidation that firmly cemented their position in the elite and remains a proud chapter in the club's modern history.