If I recall, no idea where it comes from, the USN had the ships yes. But few of them spent much time at sea. The navy also did not have the funding properly man them and also had few officers to command them. It also would likely be an issue that the US fleet rarely practiced the tactics that would be used in a fleet action, in a hypothetal war with Spain the US ships would likely make some hilarious blunders. Eventually they would learn, and sheer weight of numbers would likely still hand them a victory. But it would be interesting to see regardless.
Fair enough point, though I would merely offer that, say, unlike France post-Trafalgar, the United States has a huge supply of experienced New England sailors. They can survive the early blunders and easily fill losses.