Originally Posted by Mustard
The Australasian Championships wasn't a major in 1921, anyway. The majors in 1921 were the WCCC (an indoor wood tournament, held in Copenhagen that year), the WHCC (a clay tournament at the Stade Francis, Paris) and the WGCC (Wimbledon). The US Championships in Philadelphia were another big tournament that year, an unofficial major, due to the USLTA not being affiliated to the ILTF at the time.
The WCCC wasn't that great also. Even if they declared it a Major, for some reasons the greatest players rarely entered it. On the contrary, the WHCC was taken in high consideration.
The greatest titles "de facto" of the time were probably Wimbledon, the US Champs, and the WHCC. Moreover, the Davis Cup was maybe considered more important than them all, at least back in the days.