Complex sentence: In the World Series, they came back from a three games to one deficit, winning the final three games, the first team to come back from a three games to one deficit since the Kansas City Royals in 1985.
Split into simpler sentences: In the World Series, they came back from a three games to one deficit, winning the final three games. This was a first come back from a three games to one deficit since the Kansas City Royals in 1985.