Former world No. 4 Kei Nishikori completed his return from a long injury hiatus by winning an ATP Challenger Tour event in Puerto Rico on Sunday.
The 33-year-old defeated American teenager Michael Zheng 6-2, 7-5 in the Caribbean Open final and said his next big event is the U.S. Open, which starts in late August.
Nishikori's achieved his career-best Grand Slam at the U.S. Open when he reached the final of the 2014 tournament, which was won by Croatia's Marin Cilic.
Against Zheng, Nishikori led 5-2 in the second set but had to hold off a comeback by the 19-year-old hopeful, who drew even at 5-5.
Nishikori broke to go up 6-5 before serving out the victory, raising both fists in the air.
"Winning this tournament was more than I expected," Nishikori said. "I can't believe I could play like that. The way I played the final has made me think I could play on the (top-tier ATP) tour."
Nishikori, who last played on the ATP Tour in October 2021, underwent hip surgery in January 2022 and subsequently injured his right ankle while rehabilitating.
The Caribbean Open title put him back in the world rankings — at 492nd.