For the past 64 weeks, ever since the 2023 Australian Open, the top two spots in the WTA rankings have been held by Iga Swiatek and Aryna Sabalenka.

That duopoly could end after the Mutua Madrid Open. Sabalenka, last year's winner, is defending 1000 points this fortnight -- meaning that her current World No.2 ranking is under threat from both Coco Gauff and Elena Rybakina. Neither Gauff nor Rybakina have previously been ranked higher than World No.3.

Indeed, it's US Open champion Gauff with the inside track to No.2. With last year's Madrid points off, she has a 345-point lead over Sabalenka, 7203 to 6858. Even if Gauff loses her opening second-round match against Arantxa Rus on Thursday, Sabalenka will need to reach the semifinals to stay ahead of her. If Gauff makes the quarterfinals, Sabalenka will need to reach the final; if the American makes the semifinals, Sabalenka will need to win the tournament.

Gauff and Sabalenka are in opposite halves of the draw; if they meet in the final, the title match will decide the No.2 ranking.

Rybakina's chances of reaching No.2 after Madrid are slimmer. She will need Gauff to lose before the fourth round, and to win the title herself. Rybakina is in the same half of the draw as Sabalenka, so a title run for her would mean a semifinal place at best for Sabalenka.

If Sabalenka loses before the fourth round and Rybakina reaches the final, Sabalenka will fall to World No.4, which would be her lowest ranking since the start of 2023.