I am pretty sure most bookies brought in the match complete rule because of some of the dodgy dealings that have happened previously in tennis. I have heard that some places have a twist on that rule where they will pay out if one set has been complete, but I am sure most places these days need the match to be finished.

To be honest I was hoping Williams would retire because I thought I was screwed, right now though I am glad she fought it to the end heheheh!