Tennis: Nishikori nets another achievement by climbing to No. 4 in the world rankings

Kei Nishikori of Japan in action against Yen-Hsun Lu of Taiwan during their match at the Acapulco Tennis Open 2015 in Acapulco, Mexico on Feb 25, 2015. Japan superstar Kei Nishikori rose to fourth in Monday's new world rankings, equalling Kimiko
Kei Nishikori of Japan in action against Yen-Hsun Lu of Taiwan during their match at the Acapulco Tennis Open 2015 in Acapulco, Mexico on Feb 25, 2015. Japan superstar Kei Nishikori rose to fourth in Monday's new world rankings, equalling Kimiko Date-Krumm as his country's highest-ranked tennis player. -- PHOTO: EPA

TOKYO (AFP) - Japan superstar Kei Nishikori rose to fourth in Monday's new world rankings, equalling Kimiko Date-Krumm as his country's highest-ranked tennis player.

The 24-year-old, who is the top-ranked Asian-born man ever, tweeted: "Just saw the new rankings. Very proud of another step...#4 this week."

Nishikori, last year's US Open runner-up, now trails only Novak Djokovic, Roger Federer and Rafa Nadal after leapfrogging Britain's Andy Murray, meaning he will avoid the top three until the semi-finals at the major tournaments.

Nishikori recently won his third successive Memphis Open, his eighth ATP Tour title.

He is fast closing in on Nadal and trails the 14-time grand slam champion by just 260 ranking points.

China's Li Na blazed a trail for Asian tennis players by reaching No. 2 in the women's WTA rankings last year after winning the Australian Open, capping a remarkable career in which she also captured the 2011 French Open.

She retired seven months later with knee trouble.