Kei Nishikori hires Michael Chang as part-time coach

Japanese tennis star Kei Nishikori has enlisted the help of Michael Chang as he looks to break into the top 10 in 2014. Chang will join Nishikori's coaching staff for 17-20 weeks in 2014, Nishikori's management team announced on Wednesday.

Nishikori has been training with Chang for the last two weeks in California. The 23-year-old Nishikori rose to No. 11 in the world this year and has contributed to a rejuvenation of tennis in Japan. He won his third career title in Memphis in February.

Chang was the youngest man to win a Grand Slam singles title when he won the French Open in 1989 at 17. The 41-year-old American will be an advisory coach to Nishikori with full-time coach Dante Bottini remaining in his current role.