They ruled the tennis world in 1990s. If Federer and Nadal are the two princes currently then they both were Kings of last decade. They are none other than Pistol Pete and Charismatic Andre.
Sampras leads Agassi 20-14 in their head to head. Sampras ended every year in top five (except 1991 in which he ended the year as 6th) from 1990 to 2000. Whereas Agassi was in top 10 in almost every single year from 1988 to 2005 with two exceptions (24-1993, 122-1997).
Their games are not a bad match up by any means. Serve being Pete's best weapon and return being Andre's main strength. It’s true they are the World's best Server and Returnee respectively. They both had almost the complete all court game with no big weakness.
Neither of them were one trick pony. The only difference was Sampras being a serve and volleyer while Agassi was the baseliner. But even that added beauty on their rivalry. Andre many times stood on or well inside the baseline while returning Pistol Pete's World’s best 1st and 2nd serves.
Surface wise, they were very close in Clay and Hard. Carpet was more in favor of Pete. There is no doubt that Pete was the emperor on grass, but one of their matches (1993 Wimbledon QF) was a five setter. Let's breakup their head to head records surface-wise,
Surface Sampras Agassi
Clay 2 3
Carpet 5 2
Grass 2 0
Hard 11 9
The most important aspect of their rivalry is what follows.
Agassi was having a golden year 1995, winning seven titles and 90 percent of the matches he played, until he met Sampras in US Open final. Bases on that match we can break their rivalry into three different stages;
From To Sampras Agassi
89 1995 US Open Final 8 8
1995 US Open Final 1999 9 3
2000 2002 3 3
Pete has 5-3 in Hard court, 2-0 in Carpet and 1-0 in both grass and clay during that period.
The above numbers state that even though they were top players from 1995 USO to 1999, Agassi was suffering psychologically (particularly against Pete) for the second half of that decade due to that 1995 USO final loss. There were some personal issues which caused Agassi to drop down out of top hundred in 1997. Agassi played only 24 matches that year and obviously didn't play against Sampras.
It would’ve been further closer and more beautiful rivalry, if ”The Punisher” had shrugged of his fateful 1995 US Open loss.