WATCH: How tennis celebrated Women's Day

Friday was International Women's Day, a day dedicated to celebrating the movement for gender equality, and the BNP Paribas Open certainly took notice, with a giant pink HeForShe banner hanging on Stadium 1.

Additionally, lots of players made social-media posts about what the day means to them, and which women they take inspiration from. Serena Williams, for example, mentioned Ruth E. Carter, who won a 2019 Academy Award for her costume design for Black Panther.

Madison Keys, meanwhile, quoted Supreme Court Justice Ruth Bader Ginsburg:

CoCo Vandeweghe mentioned her mom and her grandmother:

And Tracy Austin shouted out Billie Jean King:

Bianca Andreescu quoted author Diane Mariechild:

And Denis Shapovalov, whose mom is one of his coaches, talked about how everyone has a woman who motivates and supports them.

Perhaps the biggest tennis-centric Women's Day celebration of all, though, was the marquee match on Friday, between mothers Williams and Victoria Azarenka.

Williams won it in two hard-fought sets, 7-5, 6-3. In the third round, she faced two-time Slam champion Garbine Muguruza but retired with a viral illness in the second set.

Additionally, lots of players made social-media posts about what the day means to them, and which women they take inspiration from. Serena Williams, for example, mentioned Ruth E. Carter, who won a 2019 Academy Award for her costume design for Black Panther.

Madison Keys, meanwhile, quoted Supreme Court Justice Ruth Bader Ginsburg:

CoCo Vandeweghe mentioned her mom and her grandmother:

And Tracy Austin shouted out Billie Jean King:

Bianca Andreescu quoted author Diane Mariechild:

And Denis Shapovalov, whose mom is one of his coaches, talked about how everyone has a woman who motivates and supports them.

Perhaps the biggest tennis-centric Women's Day celebration of all, though, was the marquee match on Friday, between mothers Williams and Victoria Azarenka.

Williams won it in two hard-fought sets, 7-5, 6-3. In the third round, she faced two-time Slam champion Garbine Muguruza but retired with a viral illness in the second set.