Longest winning streak by a champ - against the SAME opponent?

We're looking for the world champion, who can claim the most wins in a row against one and the same opponent.
(a draw or NC ends the streak)

The streak need not be consecutive fights, but may be found in between many other wins/losses against other opponents...
in other words: we're only looking at the fights against that one particular opponent, we're interested in.

Example: Archie Moore won 4 of 5 fights against Harold Johnson, but since the one fight he lost was the 3rd in their series...
he can claim a winning streak of only 2 against Johnson.

(As always; we're counting newspaper decisions as well as official decisions)

 

Yes, a question like this naturally makes you think of the great series between Britton and Lewis...
but 4 in a row isn't enough to win this category.

 

Good shout... but not enough!

 

Yes... but Wills was never a world champion, so he doesn't count!

 

But only 4 times in a row!

 

Ok, maybe I should have said world champion recognized by BoxRec, in order to make sure we were all on the same page.

But, hh... you're now leading the pack with 6!

 

Greb was 7-1-2 against Wenzel... but never won more than 4 in a row.