Complex sentence: In 2010, Kližan qualified for the US Open and with it his first main draw grand slam tournament appearance, he lost to former World No.1 Juan Carlos Ferrero in the first round.
Split into simpler sentences: In 2010, Kližan qualified for the US Open. In his first main-draw Grand Slam tournament appearance, he lost to former world no.1 Juan Carlos Ferrero in the first round.