Complex sentence: He made his Newcastle debut on 29 August in a match against Barnsley in which he played the full 90 minutes in a 2--0 victory, and his Premier League debut as a substitute against West Ham United on 23 September.
Split into simpler sentences: He made his Newcastle debut on 29 August in a match against Barnsley in which he played the full 90 minutes. He finally made his debut in the Premier League as a substitute against West Ham United on 23 September.