After achieving a combined ranking seventh in the world at junior level , Nishikori turned pro in 2007 .
After achieving a combined ranking seventh in the world at junior level , Nishikori qualified for his first ATP main draw event at the Countrywide Classic later that year .
After achieving a combined ranking seventh in the world at junior level , Nishikori turned pro in 2007 and qualified for his first ATP main draw event at the Countrywide Classic later that year .