Six-time major champion Carlos Alcaraz has split with his coach Juan Carlos Ferrero in a shock move.
Alcaraz, 22, has worked with his fellow Spaniard since he was a teenager, but announced on Wednesday that the pair have "decided to part ways" before the 2026 season.
Neither the world number one nor Ferrero has given a reason for the split, but BBC Sport understands Ferrero did not want to leave his role.
"Thank you for turning childhood dreams into realities," Alcaraz said in a statement.
"We started this journey when I was barely a kid, and throughout all this time you've accompanied me on an incredible journey, on and off the court.
"I've enjoyed every step of it so much with you."
Alcaraz is aiming to become the youngest man to complete the career Grand Slam at the season-opening Australian Open next month.
He has not outlined how he plans to replace Ferrero, but Samuel Lopez - who joined the team in 2024 and has led Alcaraz when Ferrero missed tournaments for personal reasons - is expected to remain.
Alcaraz started working with former world number one Ferrero when he was 15, training with the 2003 French Open champion at his academy about an hour's drive from Alcaraz's home in Murcia.
Ferrero was persuaded by Alcaraz's agent Albert Molina, who spotted the youngster aged 11 and convinced international sports agency IMG to manage him a year later, to commit to what he saw as a long-term project.
Ferrero, 45, nurtured Alcaraz's talent and took him into the professional ranks before guiding him to all six of his Grand Slam titles.
Alcaraz claimed his first major at the 2022 US Open, won Wimbledon in 2023, added the French Open and another Wimbledon title in 2024, before again winning the French Open and US Open this year.
"I wish I could have continued," said Ferrero, who once described Alcaraz as his "fourth child".
"I am convinced that good memories and good people always find a way to cross paths again."
BBC