Dude that's what I'm experiencing right now. I got involved with the tennis guys here at college and there are plenty of solid 5.0 guys that I get to play with every night now. I've never played against such consistent spin, control, and mostly pace before. I love it, but gosh it's hard to adjust to.
I agree with the other posters, splitsteps, preparation, and lots of shoulder turn are key.
But mostly it's just practice and getting used to the next level.