Kei Nishikori became the first Japanese man to break into the top 10 of the world tennis rankings on Monday.
Nishikori, who is No. 9, was assured of a place in the top 10 after beating Feliciano Lopez 6-4, 6-4 in the quarterfinals of the Madrid Open.
"It was a big goal for me to get top 10, but it's just only one week for now," Nishikori said on the ATP website. "So I have to keep playing better tennis and keep this ranking. My goal is not to get one time into the top 10. Hopefully I can keep this ranking."
The 24-year-old Nishikori beat David Ferrer 7-6 (5), 5-7, 6-3 in the semifinals in Madrid before retiring from Sunday's final with a hip injury when trailing Rafael Nadal 2-6, 6-4, 3-0.
Nishikori, who went into the Madrid Open at No. 12, had previously reached a career-high of No. 11 in June 2013.
The Japanese player beat Santiago Giraldo 6-2, 6-2 to win the Barcelona Open on April 27 for his fifth career title and his second of the year.
Nishikori becomes the first Asian to rank inside the top 10 since Paradorn Srichaphan of Thailand did so on March 29, 2004.