In Photos: Osaka wins US Open to claim Japan's 1st Grand Slam title

Naomi Osaka, of Japan, kisses the trophy after defeating Serena Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Julio Cortez)

Naomi Osaka, of Japan, holds the trophy after defeating Serena Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Julio Cortez)

Naomi Osaka, of Japan, holds up the championship trophy after defeating Serena Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Andres Kudacki)

Naomi Osaka, of Japan, is hugged by Serena Williams after Osaka defeated Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Julio Cortez)

Naomi Osaka, of Japan, holds the trophy after defeating Serena Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Adam Hunger)

Naomi Osaka, of Japan, wipes a tear as she talks with Serena Williams after Osaka defeated Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Andres Kudacki)

Naomi Osaka, of Japan, holds the trophy after defeating Serena Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Andres Kudacki)

Naomi Osaka, of Japan, is hugged by her mom, Tamaki Osaka, after defeating Serena Williams is the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Seth Wenig)

Naomi Osaka, of Japan, reacts after winning a point against Serena Williams during the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Julio Cortez)

Naomi Osaka, of Japan, serves to Serena Williams during the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Andres Kudacki)

Naomi Osaka, of Japan, reacts after breaking the serve of Serena Williams during the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Adam Hunger)

Serena Williams hugs Naomi Osaka, of Japan, after Osaka defeated Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Andres Kudacki)

Naomi Osaka, of Japan, holds the trophy after defeating Serena Williams in the women's final of the U.S. Open tennis tournament, Saturday, Sept. 8, 2018, in New York. (AP Photo/Julio Cortez)