The most normal pronounciation would be to put the stress on 'slog', not on 'dem'.
is this in a physical sense, as in to hit someone with force, or metaphorical, as in to defeat? or both?
as a native English speaker, I wrote 'thrashed' which is a common expression used by sports players in the UK, but was marked as an error - FYI
Correct me if I'm wrong, but isn't that more like "we absolutely destroyed them" rather than just "we beat them"? That's the way my mates used it in Dublin, at least.