Grigor Dimitrov has split with his coach Dani Vallverdu following a first-round beating at Madrid.
Dimitrov fell to Taylor Fritz in straight sets and then announced the decision.
"After my match yesterday Dani Vallverdu my long time coach and I sat down together," the Bulgarian wrote on social media. "After three great years, we will be going our separate ways. We had some career highlights and amazing moments on court."
The pair began working together in 2016, with Dimitrov winning Cincinnati and the ATP Tour Finals to reach a career-high No. 3 in 2017. But the 27-year-old fell back in 2018 following some poor performances and injuries, and is currently No. 46 in the rankings.
There was no mention of whether he's still working with Andre Agassi, who was brought on as a coaching consultant in 2018 and has been on the team this season.
Vallverdu previously coached Tomas Berdych, and was a longtime member of Andy Murray's team.
No new coach has been announced.