Footwork: Agassi vs. Hewitt, US Open '02

I watched a recording today of the Agassi-Hewit semifinal match at the '02 US Open. For one thing, this all-out banging back and forth is depressing. What kind of consistency does one need to keep up a rally of ten, maybe twenty exchanges, at what looks like maximum power, racquets swinging wildly and ending up way behind players' backs! When I was not mesmerized by the ball streaking back and forth, I tried to watch Agassi's footwork. I noticed that he in most cases turned completely sideways when preparing to hit, on both sides. On especially hard forehands, he ended up with his body turned in the opposite direction on the follow-through. His footwork is so quick that he has time to almost always hit from a semi-open stance.