  Sampras never dominated the tour. The only tournament he dominated was Wimbledon and mostly thanks to his great serve and the courts being extremely fast. Nadal not only dominated 0 major but an entire surface while Sampras never cared for any grass warm-up tournament.  Sampras never had a rival who could constantly challenge him, Agassi was gone for at least 0 of Sampras' prime years. Nadal since 0000 has been better and better while Federer got older. 