Complex sentence: He later coached the Golden State Warriors until 1988, achieving a winning record and a first-round playoff upset in his first season, before being fired after a terrible start to the 1987--88 campaign.
Split into simpler sentences: He later coached the Golden State Warriors until 1988, achieving a winning record and a first-round playoff upset in his first season. He was fired after a terrible start to the 1987--88 campaign.