Former US Open champion Emma Raducanu has split with coach Sebastian Sachs, her fifth coach in less than two years.
Raducanu was forced to miss the French Open and will not return for Wimbledon this year as she recovers from minor surgeries on her ankle and hands.
The 20-year-old has now dropped out of the top 100 in the women's world rankings.
"I have really enjoyed Seb's coaching and working with him, it's unfortunate that circumstances made it unfeasible for both of us to continue right now and we have decided to part ways," Raducanu posted on her Twitter account.
"I wish Seb all the best moving forwards."
Raducanu's 2021 US Open win is her only singles title as she has struggled with injuries and a revolving door of coaching staff.
She has played only 10 WTA Tour matches in 2023, winning just five, with three of those victories coming at Indian Wells before a defeat by Polish world number one Iga Swiatek.
The lack of match wins has resulted in Raducanu's drop to 107 in the rankings, meaning there are no longer any British women in the top 100. She will not qualify automatically for this year's US Open and would need to either progress through qualifying or be given a wildcard to compete there - providing she is fit enough to do so.
The absence of British talent in the singles at this year's Roland Garros has drawn criticism as only three men and no women qualified for the main draws. Britain's highest seed Cameron Norrie, the world number 13, is the lone remaining competitor after Dan Evans and Jack Draper bowed out in the first round.
Draper is another promising young British player who has been hampered by a series of injuries, having retired from his first-round match In Paris against Argentina's Tomas Martin Etcheverry with a shoulder issue.
Analysis
BBC tennis correspondent Russell Fuller
The partnership was very much in its infancy, having only begun in December.
It ultimately lasted just five tournaments and 10 matches because Raducanu struggled with a series of injuries and a bout of tonsillitis.
The 2021 US Open champion is unlikely to play again for several months, leaving Sachs with little to do. But the foundations of the relationship cannot have been strong enough to persevere.
Raducanu's recovery from surgery allows plenty of time to mull over future options, and to find the person best suited to rebuild the 20-year-old's confidence and ranking.