Former world No. 4 and 2014 U.S. Open finalist Kei Nishikori announced on social media Thursday that he will retire from professional tennis at the end of this season. The 36-year-old Japanese star, who has been plagued by injuries in recent years, missed the Australian Open in January due to right shoulder pain and also sat out last year's U.S. Open.

Nishikori turned professional in 2007 and etched his name in history at the 2014 U.S. Open, where he became the first Japanese player to reach a Grand Slam men's singles final. Though he fell in straight sets to Croatia's Marin Cilic, his run captivated fans worldwide and marked a breakthrough for Asian tennis. He later peaked at No. 4 in the ATP rankings, a career high that underscored his blend of speed, precision, and fighting spirit.

One of his most memorable moments came at the 2016 Rio Olympics, where he defeated Rafael Nadal in a thrilling three-set battle to claim the bronze medal. However, injuries have taken a toll in recent years. In early April, Nishikori admitted he was "barely hanging on" physically, hinting at the struggle behind his decision.

"Looking back on everything up to this point, I can proudly say I gave it my all," Nishikori wrote on X. "I am truly happy to have walked this path."

As the tennis world prepares to bid farewell to a trailblazer, fans can still celebrate Nishikori's legacy—a career defined by resilience, elegance, and a relentless pursuit of greatness on the court.