Tokyo - Japanese tennis star Kei Nishikori said on Wednesday he has signed up former French Open champion Michael Chang of the United States as a coach from next year.
"Excited to announce an addition to the team. Michael Chang will join us in 2014," Nishikori, who will be 24 on December 29, said on Twitter and Facebook.
His current full-time coach Dante Bottini will remain in his job, said the world's number 17, who made his ATP Tour debut in 2007 and has won three singles titles.
"We have already spent the last two weeks working hard and are getting ready for 2014," Nishikori added.
His agent, IMG Japan, said Chang, 41, will serve as a "sort of advisory coach" to use his experience in helping Nishikori "particularly on his mental side".
"Chang will accompany Nishikori to some of his tournaments and may advise him in the run-up to Grand Slam events," an IMG official told AFP.
Named the 2008 ATP Newcomer of he Year, Nishikori reached the quarter-finals of the 2012 Australian Open. His world ranking hit a career-high 11th in June this year.
Chang, known for his tenacious baseline defence and two-handed backhand shots, became the youngest-ever man to win a Grand Slam when he triumphed over Ivan Lendl at the 1989 French Open, aged 17.