We know that Rocks Pirate lost at God Valley.
But before this chapter we only knew about Roger and Garp as their enemies, now we know that there were 4 factions at war: Rocks pirates, Roger crew, Garp + Bogard and other marines, Holy Knights and at least Saturn.
So how strong do you think Xebec was back then? Top 1 on the Island?
Considering that Roger crew, marines and Holy Knights possibly were allies at same point, so it could have been almost a 3 vs 1.