He was talking specifically about Garp, that doesn't mean he never fought anybody else.
He talked a fair bit about Roger's feats, and Luffy hoping to surpass them, implying that he was part of said events.
Roger fought WB and Shiki, who were both legendary pirates of the time, as was Chinjao, ergo, Chinjao most likely fought Roger as well.
RobZilla, please read the whole conversation instead of encouraging the worthless trolls. There's nothing wrong with your post by itself, but the person you're arguing against is on Magi's side with the perfectly logical, reasonable argument of "You imbeciles need to stop taking your own vague inferences as One Piece fact." With your one-star-status, you're serving to detract from the conversation by making the various idiots that think that "All Yonkou have CoC" and "Chinjao has encountered Roger, and also all the Yonkou" are somehow indisputable facts think that they are being backed up by someone in a position of authority, even if that's not your intention.
Magi, I'm sorry most people on this board are idiots. (read: not RobZilla, though, he seemed to have just popped in randomly)