How the ATP and WTA rankings work
Both tours rank players by the points they collect at tournaments over the last 52 weeks. The further a player goes in an event, the more points they earn, and the biggest events, the four Grand Slams above all, are worth the most.
Why a player can drop without losing
Points expire after a year. If a player reached the final of a tournament last season, those points come off when the same week comes round again, and only the new result replaces them. A player who defends fewer points than last year falls, even in a good week.
Rankings and betting
The ranking is a long view of form over a whole year, and bookmakers take it into account. It says less about surface, fitness or recent momentum, which is why a lower-ranked player can still be the favourite on a given day.