I'll tell you something for nothing, even if yesterday hadn't happened, the yachting - the Prada Cup, the Christmas Cup, the America's Cup, whatever you want to call it - it has been mesmerising.

We wish the Americans no ill-will obviously, but what Barker did yesterday was all the evidence you ever needed that these things sail on the edgiest of edges.

And that is, ultimately, what great sport is all about. Pushing boundaries, enthralling us, not knowing who wins, how they win, and whether they can win.

The great question I have still not seen properly asked, far less answered, is just how is it that the Brits with that much money, and that much experience, can show up before Christmas that hopelessly prepared?

I'm not surprised they got it together. The aforementioned money and talent can generally fix most wrongs, but how they got it so wrong to start with was astonishing.

We, of course, look good. I would have said, until this weekend, probably favourites.

But that's what is making this so gripping. Such is the speed and distance covered, a half kilometre lead is nothing.  You can do 40 knots on one bit of a course, and six on another.

The real magic for me with these boats is they are a dead set leap on the catamarans. They have an agility the cats never had. I've seen tacking duels I never thought I'd see again.

Just the sight of these boats is enough. One foil, .a comparatively tiny piece of whatever it is, defying gravity to slide through the water at speeds we could once only have guessed at.

And as always in the America's Cup, it's the big picture. What do you reckon those images of this country are worth? The bright blue skies, the flotilla of fans, and the crowds on shore. Yes, there is a lot of sport being played these days, but little of it looks as good as this.

In an event that has been transformed over the years, with its colour, drama, and characters, this latest chapter of one of sports great contests is a continuation and evolution of what dreamers, geniuses, and the crazy can do if you let them.

This has been and is a real thrill.