She'll do so once more as a way to raise awareness in the fight for racial equality when she faces Victoria Azarenka in the women's singles final Saturday in Queens, N.Y
"It's a big motivating factor for me to try to get the names out to as many people as I can," Osaka told reporters Thursday. "I'm not sure if it's giving me extra power, but I want more people to talk about it."
Osaka wore a mask that read "Philando Castile" when she arrived for her semifinal match Thursday with Jennifer Brady. She defeated her in three sets to advance to the final of the Grand Slam.
Castile -- a 32-year-old Black man -- was shot and killed by police during a traffic stop in 2016 in Saint Paul, Minn.
Osaka said that when she arrived at the tournament, she brought seven masks with her -- one for each round of the Grand Slam. She wears the masks when she arrives at the court, but removes them when she plays. She puts them on again for post-match interviews.
Osaka, the No. 4 seed, began play with a three-set win over Japan's Misaki Doi in the first round Aug. 31. She wore a Brionna Taylor mask that day. Taylor, 26, was shot and killed by police in March in Louisville, Ky.
Osaka beat Camila Giorgi in straight sets in her next match and then knocked out Marta Kostyuk in the third round. Osaka wore an Elijah McClain mask for the Ciorgi match and an Ahmaud Arbery mask for the Kostyuk clash.
She wore a Trayvon Martin mask before she claimed a straight-sets wins over Anett Kontaveit. She wore a George Floyd mask for her match against Shelby Rogers, which she won to advance to reach the semifinals.
Martin's mother and Arbery's father sent Osaka supportive messages after she wore the respective masks for her matches.
"I feel like they're so strong," Osaka said, when reporters asked her about the messages. "I'm not sure what I would be able to do if I was in their position.
"I feel like I'm a vessel at this point to spread awareness. It's not going to dull the pain, but hopefully I can help with anything that they need."
Osaka has yet to wear mask for Jacob Blake, who was shot by police on Aug. 23, 2020, in Kenosha, Wis., but that could change when she arrives at the court Saturday for the tournament finale.
Osaka and Azarenka each have two career Grand Slams, but Azarenka hasn't won a major title since 2013. Osaka's last Grand Slam came at the 2018 U.S. Open.
"I've been getting more confident in myself," Azarenka said after her upset semifinal win over Serena Williams on Thursday.
The two former world No. 1-ranked players have a 2-2 record in matches against each other. Osaka, 22, is favored win Saturday's final over her unseeded foe. She beat Azarenka In three sets at the 2019 French Open.
Azarenka, 31, beat Osaka in straight sets at the 2016 Australian Open. Azarenka also captured the Western & Southern Open title a week before the U.S. Open after Osaka withdrew from the final due to a hamstring injury.
"I'm very excited, but just as excited as I was last week," Azarenka said. "I'm sure this time we are going to get to play. It's going to be a great match. It will be an amazing final. She's a very powerful player and a champion."
Azarenka began her run to the final with three consecutive straight-sets victories. She then had a string of upsets over No. 20 Karolina Muchova Sept. 7 at Louis Armstrong Stadium. Next, she beat No. 16 Elise Mertens in straight sets in the quarterfinals.
Azarenka then upset the third-seeded Williams in three sets in the semifinals to clinch a spot in the singles finale.
"She seems really confident now," Osaka said of Azarenka. "She is moving well. It should be tough when I play her."
2020 U.S. Open women's singles final
Who: Naomi Osaka vs. Victoria Azarenka
When: 4 p.m. EDT Saturday