Last year, the American won the Sunshine Double with titles at Indian Wells (with CoCo Vandeweghe) and Miami (with Safarova) and posted an 18-match winning streak on the doubles court by clinching back-to-back titles at the US Open, Dongfeng Motor Wuhan Open and the China Open, and advancing to the finals at the WTA Finals (all with Safarova).
Her streak culminated at the Brisbane International, where she won the title with Sania Mirza and rose to World No.1 - ending her partner's streak of 91 consecutive weeks at the top - before claiming the Australian Open with Safarova.
Now, Mattek-Sands' ranking is up for grabs once again in Miami. Following her loss with Safarova to Andreja Klepac and María José Martínez Sánchez, Kristina Mladenovic and the all-Russian team of Ekaterina Makarova and Elena Vesnina can challenge for the top spot.
These are the scenarios for Doubles World No.1 (as of 3/27/17):
Mladenovic (playing with Svetlana Kuznetsova) would need to reach the final to have a chance of overtaking Mattek-Sands at No.1.
Makarova and Vesnina could move to co-No.1s if they win the title and Mladenovic does not reach the final.
Here's where the No.1 contenders are in the doubles draw:
Mladenovic and Kuznetsova: The unseeded duo recovered from 6-0, 4-1 down against Chan Hao-Ching and Raquel Atawo to win a decisive 10-1 match tie-break and reach the quarterfinals, where they will play No.4 seeds Andrea Hlavackova and Peng Shuai.
Should they reach the semifinals, a potential matchup with Brisbane finalists and Dubai champions Vesnina and Makarova awaits.
Vesnina and Makarova: The No.2 seeds have dropped just four games through their first two matches, and will play an unseeded pair in the quarterfinals: Gabriela Dabrowski and Xu Yi-Fan, or Lara Arruabarrena and Liang Chen.