Tokyo, Oct 15 (IANS): Japanese tennis player Kei Nishikori said on Tuesday that he had split with his coach of eight years, Argentina's Dante Bottini.

Nishikori began working with Bottini in 2011 and won almost all his titles under the Argentine's tutelage.

"After 9 years of working together literally day in and day out, I have decided it is time for a new voice," the Japanese player wrote on his Twitter account along with a smiling photo of the two together.

Nishikori, who has been sidelined by a right elbow injury, expressed gratitude for his former coach's contributions to his career and said the two will "remain very close friends", reports Efe news.

"I appreciate so much the last 9 years and our friendship," he said in the tweet without mentioning who would be Bottini's successor.

Under Dante, the 29-year-old Japanese tennis player won 11 of his 12 ATP titles, won bronze at the 2016 Rio Olympics and climbed to number 4 in world ranking.

Nishikori, currently ranked world no. 9, was planning to return to action at the Vienna Open, which will be held between October 21-27, but had to end the season prematurely to recover from his injury.