Novak Djokovic parts with his entire coaching team before Madrid Open
Twelve-time Grand Slam winner Novak Djokovic has parted company with his entire coaching team, including Marian Vajda, who has been with him through almost all of his career.
Djokovic believes this "shock therapy" will help him achieve better results.
The world number two says he will be on the tour alone until he finds the right person to take over as head coach.
Boris Becker, a six-time Grand Slam winner, left in December after three years as the 29-year-old's coach.
The Serb next competes at the Madrid Open, with the men's first-round draw to take place on Friday.
A statement on Djokovic's website said he and coach Vajda, fitness coach Gebhard Phil Gritsch and physiotherapist Miljan Amanovic had "mutually agreed" to "end their successful and long-term partnership".
Djokovic said he would be "forever grateful" for their "friendship, professionalism and commitment to my career goals".
"Without their support I couldn't have achieved these professional heights, but we all felt that we need a change," he added.
"My career was always on the upward path and this time I'm experiencing how it is when the path takes you in a different direction.
"I want to find a way to come back to the top stronger and more resilient. I am a hunter and my biggest goal is to find the winning spark on the court again."
Djokovic lost his world number one spot to Britain's Andy Murray in November last year, after 122 weeks at the top of the rankings.
He beat Murray in the final of January's Qatar Open, but was knocked out in round two of the Australian Open later that month by Denis Istomin, then the world number 117.
In his five events since he has failed to advance beyond the last eight, most recently losing to Belgium's David Goffin in the Monte Carlo Masters quarter-finals.
Russell Fuller, BBC tennis correspondent
There was no great surprise when three very successful years with Boris Becker came to an end in December - head coaches tend to come and go - but this will have been a more agonising decision for the 12-time Grand Slam champion.
Marian Vajda, in particular, is woven into the fabric of Djokovic's career - "shock therapy" is an excellent way to put it.
Vajda says he is "convinced" the world number two will remain at the top for many years. Becker said something similar late last year, and both may prove to be right.
For now, though, the sport is waiting to see whether Djokovic still has the hunger required after such a phenomenal and sustained spell of success.