Complex sentence: He was given the number 10 shirt and made his debut a day after he signed the contract, making an immediate impact by being on the winning side in the Milan Derby (4--0) against A.C. Milan.
Split into simpler sentences: He was given the number 10 shirt and made his debut a day after he signed the contract. He made an immediate impact by being on the winning side in the Milan Derby (4--0) against A.C. Milan.