Each week tennis stars are ranked according to their position within the world. These rankings are taken as seriously as credit scores as they can affect the earnings potential for players in endorsement deals and even play a part in determining not just who is invited to the top tournaments, but where they fit into the us open, wimbledon or french open schedule .

The ATP World Tour rankings are used for the grand slam tournaments and the World Tour Masters 1000 tournaments. In all, there are 19 tournaments that earn points for players throughout the year. The highest ranked players qualify for the Barclays ATP World Finals .

The actual point system is quite complicated. Playing french open tennis or in another grand slam event earns more points than other tournaments. A win in any of the big four is worth 2000 points, versus 1500 or less for other tournaments. Points are distributed for each round, so that even those who lose in the first round of play accumulate a minimum number of points.

There are specific rules about qualifications, penalties and injuries. For instance, the top players of the previous year are expected to play in the next year’s grand slam events. If they do not, they can have their rank dropped. Points earned are also compared to previous performance, so that someone who does well at the French Open one year and poorly the next can actually lose points and find themselves falling in the rankings.