"Steinitz had an even record against Adolph Anderssen. Paul Morphy's record against Anderssen was +12 -3 =2. He would have EASILY beaten Steinitz. Just FYI"
Kasparov scored 16-0 against Shirov, Kramnik had a minus score against Shirov in 2000. Kasparov would easily have beaten Kramnik in 2000, at least until the match actually was played.
(a persuasive and well-researched post)