David Goffin, the first Belgian player ever to break into the world's top 10, announced on Friday that he will retire at the end of the season.
The 35-year-old, who reached a career-high ranking of world No 7 in 2017, won six titles on the ATP Tour and reached nine other finals.
"All these years at the highest level have taken a toll on my body," he said in a video posted on social media.
"The knee injury I suffered last year played a decisive role in my decision to stop."
A professional since 2009 and currently ranked down at 156, Goffin never made it further than the quarterfinals of a Grand Slam.
He reached the last eight at Roland Garros in 2016 and the Australian Open the following year.
Goffin also made two quarterfinal appearances at Wimbledon in 2019, where he lost to eventual champion Novak Djokovic, and 2022.
He played a key role as Belgium reached the Davis Cup final in 2015, when he lost the deciding rubber to Britain's Andy Murray, and 2017 when they again finished as runners-up to France.
In the wake of that second Davis Cup final, he went on to reach the final of the ATP Finals in London, defeating Rafael Nadal and Roger Federer before losing to Grigor Dimitrov.
"I gave everything to tennis, and this sport has given me far more than I ever dared imagine," he said. "That's what makes my decision so difficult."