Complex sentence: Nishikori opened his hard-court season by participating in the Citi Openand reached the quarterfinals only to be beaten by Richard Gasquet for the fifth time in his career in straight sets.
Split into simpler sentences: Nishikori opened his hard-court season by participating in the Citi Open. He reached the quarterfinals only to be beaten by Richard Gasquet for the fifth time in his career in straight sets.