Complex sentence: He played for the Italian national team for more than ten years during which he became almost irreplaceable as the main defence pillar and gave a significant contribution to the team's victory in the 1982 FIFA World Cup.
Split into simpler sentences: He played for the Italian national team for more than ten years during which he became almost irreplaceable as the main defence pillar. He gave a significant contribution to the victory of the Italian team in the 1982 FIFA World Cup.