Patrick Mouratoglou said a pregnant Serena Williams is as hungry as ever to add to her record haul of grand slams and does not expect the legendary American to retire while she can still challenge for major titles.
Williams is due to give birth to her first child in September, but the 35-year-old is already making plans for a tennis comeback.
The 23-time major champion has been supporting her sister, Venus, at the French Open this week and has also been discussing her return to the game with her coach, Mouratoglou.
Frenchman Mouratoglou said the world number two retains a huge desire to claim more grand slam titles as she prepares for motherhood.
He told Omnisport in Paris: "We had a talk here this week and we had already talked before. When she told me she was pregnant, at the same time she also told me she wants to come back.
"She asked me if I could wait to work with her when she comes back and I said of course I will. This week we spoke and she wanted to have a discussion over what we will do, when I would start working with her again and which team we would use in order to get back."
Asked if Williams still has a big will to win major titles, he added: "She definitely has and since she feels she can still win grand slams, I think it will be difficult for her to stop.
"I think it will be difficult for her if one day she thinks she is not good enough to win grand slams, then it is going to be a different story.
"For now, she believes."
Mouratoglou said it is anybody's guess as to how long Williams can continue challenging for honours.
"I am not going to put any limits on her. Who knows, she has showed me several times that normal limits do not apply to her," he said.
"She thinks differently [to other players], she doesn't put any limits on herself.
"Her level of expectation is really high, she sets new goals every time she reaches one, physically she is a better athlete than anyone, she has a huge game and if you put all those things together it's very dangerous."