Japan Open: Kei Nishikori retires from tennis after defeat by Frances Tiafoe in Tokyo

Kei Nishikori, the former world number four, retired from professional tennis following a 6-4 6-4 defeat to world number eight Frances Tiafoe at the Japan Open in Tokyo. The 36-year-old, widely regarded as one of the best players never to have won a Grand Slam, was visibly emotional after the match. Nishikori had been a trailblazer for Japanese tennis, becoming the first Japanese man to reach a Grand Slam final at the 2014 US Open.