The 76-year-old is widely regarded as one of the greatest managers in history and coached some of the greatest names during his time in the dugout.
Capello was speaking to GameInsight and stated that it would be impossible to select his top 11 players. However, he reserved special praise for the Brazilian icon despite the difficulties in coaching him.
“It is impossible to make a top 11 because there would be about 30 players who deserve to be inside. I can say one thing though, that is, the best player I coached was Ronaldo. But that's what has done me the most damage."
“I had to send him away in order to win the championship. But he was the best of all."
The two men linked up briefly at Real Madrid for a few months in the 2006-07 campaign before Ronaldo was sold to AC Milan midway through the season.
Los Blancos went on to win the 2006-07 La Liga title on goal difference to end a three-year trophy drought before sacking Capello.
Ronaldo Nazario emerged as a precociously talented teenager and had one of the most spectacular starts to a career in footballing history.
O Fenomeno set several records in his early career with Cruzeiro, PSV, and Barcelona, and remains the youngest player in history to win the Ballon d'Or.
He represented other iconic clubs including Inter Milan and AC Milan, as well as the Brazilian national team.
Despite injury-blighted career, Ronaldo still widely regarded as the greatest centre-forward in history
Ronaldo was an unstoppable force in his prime and is arguably the most complete striker in the history of the game.
The three-time FIFA World Player of the Year was blessed with speed, technique, strength, dribbling, and an innate finishing ability that is perhaps unmatched in history.
However, he was blighted by persistent injuries that reduced his output when he was about to hit his peak.
Despite this, the Brazilian legend was able to showcase his abilities on the biggest stages. Having failed to guide his nation to glory at the 1998 FIFA World Cup, he returned four years later to give his most career-defining performance and fire Brazil to her fifth global title.
His lack of UEFA Champions League glory is one asterik in his career and the Rio native is arguably the greatest player to never win Europe's biggest club prize. Nevertheless, it takes nothing away from what was a spectacular and iconic career.