Originally Posted by ark_28
To be fair that comparison is a little ridiculous! they were not masters when Pete played but super 9's and never truly carried the same weight as they did now. Had they done so Pete would have had closer to 20 and focused more on the masters he used them as tune up events and skipped a bunch of them!
The ATP dates records in Masters tournaments from 1990 even if they were not called 'Masters' at that time.
According to Wiki:
"The series was introduced in 1990 with the inception of the ATP Tour by bringing together the nine most prestigious tournaments of the Grand Prix Tour Championship Series (1970–1989). The events were originally known as the ATP Championship Series, Single Week for the first three years. From 1993 through 1999, the series was known as the Mercedes-Benz Super 9. In 2000, the name was changed to the Tennis Masters Series and then changed to ATP Masters Series in 2004. The present name took effect in 2009."
As for Sampras, he has gone on record as saying that he sometimes found them harder to win than Slams as you often had to play back to back matches against top players often without a day's rest unlike in the Slams.