I think of the rise of extreme grips like the Western grip used by Rafael Nadal and Dinara Safina as recent developments in the modern game.
Here's proof that it was around as early as 1933, at least in France. That's when French painter Balthus created "The Street." This budding tennis player is one of several strange figures in the painting.
Check out that grip! And how she's pointing to the oncoming ball with her non-racquet hand! She's even got her weight on her back foot, ready to release into the shot as she follows through.
All she needs is some strings in her racquet and a ball with some bounce left in it and it's game on.
Here's the bigger picture, without glass glare.