The 2012-13 campaign was a season of soaring ambition for Sparta Rotterdam as Kasteelheren finished a strong 3rd in the Eerste Divisie, mounting a serious challenge for a return to the top flight. Leading the charge was the prolific striker Sandro Calabro, whose 19 goals powered the team to the promotion play-off final. Despite this strong league form, the campaign ended in agonizing defeat to Roda JC in the final stage of the play-offs. It was a year that cemented their status as a major force in the second tier and remains a defining, if heartbreaking, chapter in the club's modern history.