Daniil Medvedev felt he had no choice but to withdraw from his home tournament in Moscow after a gruelling schedule.
It was announced on Tuesday that world number four Medvedev would not take part in the Kremlin Cup, foregoing the chance to reach a seventh consecutive final on the ATP Tour.
Final number six ended in victory over Alexander Zverev at the Shanghai Masters last Sunday but, after 59 wins on tour this year, the US Open finalist felt taking to the court once again this week would have been a bridge too far.
"Nobody knew that I would do so well in Shanghai to reach my sixth final in a row," Medvedev told ATPTour.com.
"I just feel that I am physically and mentally exhausted. I can't be 100 per cent. As a professional, I cannot step on court knowing that I am not 100 per cent ready to play.
"On the one hand, it is very sad, because I really wanted to play in Moscow in front of my home crowd. I've played for four years in a row in Moscow and each year my results improved.
"But, on the other hand, this is how it is. It is professional sport, and I must do what is best for my body. In this situation, I had no choice."
However, Medvedev was keen to allay fears over his readiness to compete at the season-ending ATP Finals in London next month, and he is slated to return to action at the Vienna Open next Monday.
"I feel amazing and have a great mood," Medvedev added. "I've never dreamed about six finals in a row."