omg! a poster with something intelligent and productive to say! marry me?
I agree with your main point: putting pressure
. I think we all agree that the benchmark to compare anyone's tennis right now are the Williams, that is the tennis that rules right now. I was watching Williams against Daniliidou, and I couldn't stop thinking that serving like that there was not a chance in hell Eleni'd win. Serving well and returning well are the main issues, I think. I think once the rally gets started, there are plenty of players that can rival the sisters, but the thing is they don't let you start the point. It's bam wham thanks for trying.
Whenever I have seen players putting pressure on the sisters it's mostly been people that return well, like Monica or Chanda. The thing about returning well is that you can't practice anticipation, you either have it or not. But you can improve your reflexes and your speed getting to the ball, you can practice how to block the ball... if I was out there on the tour, I'd be practicing my returns against a hard serving dude.
Then of course if you can mix it up a bit during the rallies, you have a big advantage, everyone is hitting flat these days, the only problem with a flat hard ball is getting there, if you are fit enough, they are easier to control than ones with heavy topspin. Anyone on tour doing something slightly different: serve and volley, heavy topspins, moonballing, etc, has an edge, since the other players (sp. below top30) won't be used to that.