🎉 Hooray for the little one!
I've had that issue before too with the first one out playing soccer with the rest of the eggs haha. But iirc it's still best to keep them in the incubator for 12-24 hours. And preferably until a second duckling hatches, because a single duckling will have a harder...
I didn't see it mentioned but what type of duck are they? Muscovies take a few days longer than Mallard-related ducks iirc.
For what it's worth, I've always used a Nurture Right 360 myself and have successfully incubated and hatched a few of a clutch of duck eggs that their mother couldn't...