Before Kenedy even took the pitch for his team's Asia tour last week, the 21-year-old Brazilian posted 2 videos on social media.

The first contained the caption, "Porra china" -- which some have translated to, "F*ck China."

The second showed an image of a sleeping Chinese security guard with a caption that translates to, "Wake up China, you idiot."

As you can imagine, the Chinese were PISSED ... with one powerful newspaper printing an editorial trashing the guy for "humiliating China" and suggesting he be kicked out of the country.

But Chelsea sent him packin' first -- and then issued a statement saying the player had been "strongly reprimanded and disciplined."

Kenedy tried to apologize ... but it was too late.

What an idiot.