Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
After the second day of matches was canceled due to rain, the first-round match between Tsonga and Melzer was converted to a single 'pro set' (first to eight games, by a margin of two) instead of the standard best of three, in order to save time and enable the second-round matches to be played later on the same day. (Melzer won 8-6).
The play-offs were also delayed and ultimately cancelled due to rain delays.