The Russian talked openly of his struggles after Saturday's win over Jannik Sinner.
The Italian was struggling physically during his loss to Rublev in Montreal on Saturday night.
The 20-year-old says she took a lot from mingling with American stars such as gold medal winners Sydney McLaughlin-Levrone and Gabby Thomas.
The Greek shared the news on social media on Friday.
The Greek sent a message to his father and coach through the media.
The 24-time major champion will take some rest before the US Open.
"It hurts. It hurts. It hurts," said Grigor Dimitrov after surviving every male player's nightmare in Montreal.
