World No. 11 Stefanos Tsitsipas announced a split with his coach -- his father Apostolos -- on Friday.

The 25-year-old Greek star's decision came one day after his second-round loss to Kei Nishikori in Montreal.

"It is with a heavy heart that I inform you that my collaboration with my father as a coach has come to an end. I prefer to keep my father in his role as a father, and only as a father," Tsitsipas wrote in Greek on social media, per the ATP Tour website.

Tsitsipas won 11 tour-level titles under his father's guidance, including the 2019 Nitto ATP Finals. He still is looking for his first grand slam win, having reached the final at the French Open (2021) and Australian Open (2023).

"Philosophy teaches us that wisdom comes through understanding our limits and acknowledging our mistakes," Tsitsipas continued. "In my case, I realized that I was wrong to talk to my father the way I did. Tennis is not just a match, a hit or a performance of a few seconds. It is a long journey full of emotions, pressure and expectations.

"In that moment of frustration, there were many mistakes and errors on the part of my coach and father. As an introvert, I tend to hold in my emotions and build them up until I reach a bursting point. I consider myself patient, so the fact that I reacted this way left me shocked."

Tsitsipas and his father briefly parted ways in 2023 after he hired Mark Philippoussis, a relationship that ended after just two months.

--Field Level Media