Complex sentence: In July 1973, when Berra's Mets trailed the Chicago Cubs by 9½ games in the National League East; the Mets rallied to win the division title on the final day of the season.
Split into simpler sentences: In July 1973, Berra's Mets trailed the Chicago Cubs by 9½ games in the National League East. The Mets rallied to win the division title on the final day of the season.