It might well be a smackdown of the US fleet. I think though, it would accelerate the build of the "New Navy". Nothing gets your attention more than an unexpected beat-down, when you think you are an up-and-comer....
I'm not sure of the impact on Spain. It would be a great morale booster on the home front, but wasn't Spain's economic situation in the 1870's-1900 a bit rocky? The OTL Spanish American War had them with some nice ships, in varying states of completion, with a lot of old hulls in pretty decrepit condition (Much like the US fleet of 1873...)