Canada's Milos Raonic parted ways with coach Carloa Moya despite a season which saw him reach his first Grand Slam final and finish at three in the world.
The 25-year-old only teamed up with former French Open champion Moya in January before adding John McEnroe briefly to his coaching set-up in the summer.
The big-serving Canadian was runner-up to Andy Murray at Wimbledon in July.
He also made the semi-finals of the World Tour finals in London before ending 2016 at a career-high three in the world behind top-ranked Murray and Novak Djokovic.
“Thank you to Carlos Moya for helping me tremendously this year, alongside my team, to get the best out of me,” tweeted Raonic.
“Under Carlos' direction and tutelage I have played my best yet to date. We will no longer be continuing our coaching relationship but remain close friends. I wish him all the best.”