ROY JONES JR FALLS FOR A RUSSIAN CHICK . . . THEN GETS BRUTALLY KNOCKED OUT!! (MAKEOUT PICS)

Boxer Roy Jones Jr had a GOOD WEEK . . . and a bad one.

You see, he was in RUSSIA for a boxing fight this past week. While there, we're told that Roy met up with a BEAUTIFUL RUSSIAN GIRL . . . a SVETLANA as we like to call them. The two hung out ALL WEEK . . . and really took a LIKING to each other.

And now the BAD part. While Roy was ENJOYING himself around Russia with his new found SVETLANA . . . he wasn't TRAINING like he should.

And the result of all that partying . . . Roy got brutally KNOCKED THE F*CK OUT in his fight . . . with just 12 seconds left.