Former Wimbledon finalist Philippoussis, who joined Tsitsipas's coaching team last season and helped guide the world No.5 to the Australian Open final in January, confirmed the split on Instagram earlier this week.
Tsitsipas, whose main coach remains his father Apostolos, explained on Friday: "It's never easy having two coaches on the court.
"I know they are there to help and give the best they can, and provide for me, but sometimes it can get quite kind of hectic having two coaches share opinions.
"I'm at a phase of my career in life where I need one coach that can provide all the information, all the analysis, all of the things that I'm looking for to improve my game. Less is more, in my opinion.
"It is very important to stick with few people, in my opinion, and make that work, because when you have a lot of people around you, it can get very draining for your mental energy, too."
Tsitsipas added that his split with Philippoussis, who also made a US Open final, was a "mutual decision".
"I have had weeks where I just travelled with my coach because that's how I felt it should have been done and I don't regret any of it, because it's a personal feeling," Tsitsipas said.
"I love Mark. He's an amazing person, and we still stay in touch with him very often."
Tsitsipas, whose first-round match in Paris will be against Jiri Vesely, has been in fine form during the clay swing, reaching the quarter-finals in Monte Carlo and Madrid, the final in Barcelona and the semi-final in Rome.
The 24-year-old, who will be hoping to claim a first grand slam title at this year's French Open, said he has been trying to play with the same mindset he had during his run to the 2021 Roland Garros final.
"It was a great two weeks of tennis for me, and I do remember how I did things and I do remember what worked better for me during these two weeks in Paris," Tsitsipas said.
"My capacity is big and grand, and I can feel it. I just need to get a few good first matches to keep believing that I actually can do something this year."
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