Kei Nishikori celebrates his 28th birthday on December 29th.
Alexander Zverev gave Nishikori the gift of advancing age in August.
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The 20-year-old German swept Nishikori in the Washington, DC semifinals, in a loss that was a learning experience for the 2014 US Open finalist, who played only one more match before pulling the plug on 2017.
“Seeing Zverev definitely made me feel old,” Nishikori told The Japan Times. “It’s rare to see a player that young play so well nowadays. I know I’m not considered a young player anymore. Of course, I feel pressure in that sense but that’s the reality.
“Young players are always aggressive and unafraid. That’s their weapon and I can learn from that.”
Injury-induced inactivity has caused the former world No. 4's ranking to fall to No. 22.
A nagging right wrist injury forced Nishikori to close the curtain on his season after he blew four match points falling to Gael Monfils in his Montreal opener.
Instead of surgery, Nishikori opted to rehab his right wrist, a process that is ongoing. The owner of 11 ATP titles told the Japanese media he spends about three to four hours a day rehabbing his wrist.
Currently, Nishikori is limited only an hour on court a day at the IMG Bollettieri Academy in Bradenton, Florida.
“There was a lot of good that came from this experience,” Nishikori said. “If it weren’t for the injury I wouldn’t have undergone a rehab period in Europe and I wouldn’t have met the physical trainer who introduced me to a conditioning method that was new to me. I feel like it could change my body.”
Nishikori, who was runner-up to Stan Wawrinka in Brisbane last January and pushed Roger Federer to five sets at the Australian Open, is entered into Brisbane next month.
However, he told the Japanese media he will not return to tournament tennis until he feels fully fit.
“I can’t say when I’ll heal from my injury so I’m trying not to rush anything,” Nishikori told The Japan Times. “I’m aiming for the (January 1-7th) Brisbane International, but it could be February, or even March, who knows.
“I want to make sure I’m in top form when I’m back on tour so I’m in a position to win a Masters or Grand Slam title. I also hope I’m mentally stronger and hungrier next season."
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