Kei Nishikori has faced many setbacks in recent years which have returned once again in 2025.
Nishikori reached the US Open final in 2014 and has been ranked as high as world number four.
However, the Japanese star has dealt with various injuries since then, with Nishikori falling outside the top 750 after undergoing hip surgery in 2022.
Despite returning to the top 60 earlier this year, Nishikori has been forced to miss three Grand Slams in 2025 and had not won a match in six months.

Kei Nishikori wins his first match since May after returning to tennis
Nishikori had not played a match since losing in the first round of the Cincinnati Open, before he withdrew from the US Open.
It had been even longer since he last won a match, which came when Nishikori beat Learner Tien at the Geneva Open.
During the time since his last match, Nishikori had split from his coach and former Australian Open champion Thomas Johansson, who is now working with Daniil Medvedev.
After recovering from the back issue that forced him away from competition, Nishikori made his return at the ATP Challenger tournament in Yokohama, Japan.
Despite losing the first set against his world number 793 compatriot, Nishikori fought back to beat Taisei Ichikawa, 4-6 6-1 6-1.
Will Kei Nishikori play the Australian Open next year?
After being absent from the match court, Nishikori has been unable to defend the ranking points he gained at this stage of the season last year.
As a result, Nishikori has fallen outside the top 150 and is currently the world number 158.
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Regardless of what Nishikori achieves at the ATP Challenger tournament in Yokohama this week, he will still not be able to climb back into the top 100.
This means that Nishikori will be unable to directly enter the Australian Open next year, and instead will be in the qualifying draw.
The only other way that Nishikori could have got into the Australian Open main draw was if he won the Asia-Pacific wildcard play-off that takes place every year.
However, Nishikori does not appear on the entry list for this and instead will likely need to play qualifying at a Grand Slam for the first time since 2010.
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