Patrick Mouratoglou announced on Thursday that he will be working with former World No.1 Simona Halep, casting a doubt over near future of Serena Williams.
Mouratoglou, who has famously coached Williams for a decade, said he is ready to start a new chapter in his life.
“In the last 8 months, I realized how much I missed coaching,” Mouratoglou wrote on social media. “It is the passion of my life, and I still feel like I have so much to give.”
Last September, Halep and her longtime coach Darren Cahill had parted ways.
Halep, a two-time Grand Slam winner, had gone to his tennis academy ahead of Indian Wells in early March.
“At the end of the week, she asked me if I was available to coach her,” Mouratoglou said.
“I have the highest respect for her, but it was out of the question at the time.
“A few weeks later, I had a conversation with Serena, and the door opened for me, at least short term, to work with someone else. I will keep you updated on what’s coming next soon.”
Williams, who owns 23 Grand Slam titles, one behind all-time leader Margaret Court, has not played since injuring her hamstring at Wimbledon last year.
With Mouratoglou, the 40-year-old Williams won 10 majors.
Halep has claimed one WTA title this year. The Romanian won the WTA 250 event in Melbourne before falling in the fourth round of the Australian Open. She was also a semifinalist in Dubai and Indian Wells.