It is not hard to understand that people coming before Mihawk are weaker than Mihawk.
The strongest comes last, it is that simple. Nobody is confirmed above Mihawk.
And only one guy will be in the future.
The one who will end up with even strongest haki than Mihawk's which forged the strongest weapon in all of history.
There is nothing friendly about Zoro vs Mihawk.
It is the ultimate fight of the whole story.