MELBOURNE, Australia - At the start of the 2019 Australian Open, 11 players had a chance to leave Melbourne with the World No.1 ranking. After six days of play, that number has narrowed to seven players who remain in contention for the WTA's top spot, with No.2 Angelique Kerber, No.4 Naomi Osaka, No.5 Sloane Stephens, No.6 Petra Kvitova, and No.7 Elina Svitolina, and No.8 Karolina Pliskova in the hunt. 

Here are the relevant Round of 16 matches that carry No.1 ranking implications:

Sunday: Bottom Half 

No.2 Angelique Kerber: vs. Danielle Collins
No.5 Sloane Stephens: vs. Anastasia Pavlyuchenkova
No.6 Petra Kvitova: vs. Amanda Anisimova

Monday: Top Half 

No.1 Simona Halep vs. Serena Williams
No.4 Naomi Osaka vs. Anastasija Sevastova
No.6 Elina Svitolina vs. Madison Keys
No.7 Karolina Pliskova vs. Garbiñe Muguruza

World No.1 Scenarios:

At the close of Day 6, here are the minimum rounds each player needs to have a chance of moving to No.1 after the Australian Open:

Semifinals: Stephens, Osaka, Kvitova
Final: Kerber, Svitolina, Ka.Pliskova

The following chart illustrates each player's point total as they progress through the tournament: