Andre Berto knows all about knockouts ... but the boxing stud says he knows a little something about knockers too -- telling TMZ Sports there's one pair in Hollywood that stand out above the rest ... BY FAR!!

Berto was at Greystone Manor in L.A. this weekend when our photog asked him (in honor of breast cancer awareness month) who has the wappiest wappers in all of Tinsel Town.

Check out the clip -- anyone expecting Berto to pick one of the usual suspects might be a little surprised ... 'cause the woman he "Singled Out" is no "New Kid On the Block."

FYI -- Those were like, hints.

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