Recovering from an illness, i have some time to look again into some stats of the old pro tour, mainly based on McCauley's book and on the fine stats of Andrew Tas, which pc1 provided. Its for me a valuable source to see the domination of the pro champs, of course this is not the end of the debate and there are some caveats for evaluation. 1. The percentages seem lower than for some champs of open era, like Borg or Federer, who were over 90 % percentage in peak years, or like Nadal, who is over 83% lifetime. It was however a different structure of the tour, with small fields, many match series, always against the top players. Think for a moment, if Federer would still be on 90% with facing Nadal over 20 times a season. Players like Laver or Rosewall actually had better percentages in open era, when they were already quite old, than on the pro tour. Laver was 80% between 30 and 40 in open competition. You see the difference also to the Amateur Play, where those players won over 90% in some years with their many, many matches. Rosewall was 90-10 in his last am year 1956, Laver had a staggering 151-15 in his GS year 1962 (and 139-21 in 1961). In 1969 Laver was 102-15 in tournament play, 1970 90-15, when he was already 32. Rosewall was 54-23 in 1969 and 71-21 in 1970. 2. There was a shift from match series to more tournament play since around 1964-1965, although until 1967 a mix between those formats further existed. Especially the World Series of hth matches should be considered, because those long series counted heavily on he stats, especially on the new pro who lost consistently to the older champ, like Gonzalez, Rosewall, Hoad or Laver did initially(i have marked them separately in my count). The numbers are still incomplete, and maybe my eyes were not good enough anymore, to see all the results properly. So i would be glad to get some help, corrections and additions by other posters, who are more familiar with the stats world.