You can choose what stats you use to rank your teams and how to rank your players.
In the Stats Model Editor (Menu > Manage > Statistics | Standings > Stats Model Editor)
Click on Model for Players
The bottom left section fills up with the current columns displayed for the Singles Stats.
The bottom right section fills up with the columns used for Ranking the Singles Stats.
How the Ranking works
The top field is the one used unless there is a tie, then the second one is used and so on.
In this example, Score + is used to rank (highest score is first), if tied, the wins are used. If also tied, the losses are used (lowest count is ranked higher) :

To change the Ranking
Click on the + in the bottom right section
Check all the columns you want to use to Rank the Singles Stats (and uncheck any that you don't need). Click on OK when done.
Order the fields to rank by the first on top, if tied, it looks at the next and so on.
In the example below, the player with the highest score would be ranked first, if score/points is tied with another player, it will go by wins, then losses.
                 