Former world number one Maria Sharapova and coach Sven Groeneveld have agreed to part ways after a four-year partnership.

Sharapova, 30, made the announcement on Friday, following the Russian star's shock first-round exit at Indian Wells, where she was upstaged by Naomi Osaka.

The five-time grand slam champion and Dutchman Groeneveld teamed up in 2014, winning seven titles together, including the 2014 French Open.

But Sharapova – who returned from suspension in 2017 – has struggled for form this year amid a run of three consecutive defeats.

"After four successful and challenging years of collaboration together, I would like to thank Sven for his incredible loyalty, work ethic and most importantly the friendship that we have formed that will go beyond this working partnership," a statement on Sharapova's website read.

"Although we have mutually agreed to part ways during this time, I have been incredibly fortunate to have a team leader like him in my corner for the past four years."

Groeneveld added: "Maria has been one of the most hardworking and professional players I have ever worked with. Her strength and fighting spirit will continue to be a force to reckon with and I have the deepest respect for her as a player and person."

Sharapova holds a 5-4 win-loss record this year, which includes a run to the third round of the Australian Open at Melbourne Park in January.