Asked about the political chaos in his native Spain on Monday, Nadal said he was deeply saddened by the events.
Catalonia, which has Barcelona as its capital and has its own language and culture, is seeking independence from Spain.
Like many, Nadal was shocked by the scenes of police brutality as security forces cracked down on the Catalonian referendum to vote on independence, which went ahead despite the Spanish government declaring it to be illegal.
“I want to cry when I see a country where we have known how to co-exist and be a good example to the rest of the world get to a situation like this,” said Nadal, who is Beijing this week to take part in the China Open.
“I think the image we have presented to the world is negative.”
Nadal admitted it was not easy to see events unfold as they did, especially viewing it from afar.
“It was a sad moment, my heart sank all day,” he added.
“Moreover, from here, at a distance, you experience it differently.
“I have spent many parts of my life in Catalonia, important moments, and to see society so radicalised surprises and disheartens me.”
Nadal will play his opening match at the China Open on Tuesday.