Well, the period from 3:3 in the first set to 3:1 in the 2nd set has to the best tennis that anyone player has put together against another man who was playing damn well, Sampras won 5 games in a row to really open up the final plus really he should have had a double break in the 2nd set because Agassi was struggling on literally every service game for most of the 2nd set.
Sampras hit a high level of grounstroke winners - both Pat Cash and Michael Stich said that Sampras matching Agassi in the baseline battles will be a key part of the match, also interesting because Sampras wasn't staying back on his second serve like he would on hardcourts, so those winners came on Agassi's service games - so he was really dominating Agassi from the net and the baseline. The grass court that year was quite firm and high bouncing, giving Agassi the platform to do well and get to the final.
In fact, Agassi's 3 set defeat of Rafter in the semifinal is some of the best tennis I've ever seen Agassi play - so really both men were in top form going into that final, although Agassi was made slight favourite because of his hot streak and the media figured (or hoped) that Sampras' run had to come to an end, they were saying the same things about Sampras in 1998.
Here's extensive clips of the match I put on youtube recently:
By the way, looks like youtube have really improved the flash recenty - at last.