Coco Gauff is the youngest player to qualify for the WTA Finals in singles since Maria Sharapova.

After an outstanding season that included reaching her first grand slam final at the French Open, the 18-year-old world No. 7 has achieved the rare feat of reaching the year-end tournament in both singles and doubles.

Gauff, who advanced to the third round of the Guadalajara Open by defeating Elisabetta Cocciaretto 7-6 (7-1) 6-3, will be the youngest participant since Sharapova in 2005 and the youngest American since Lindsay Davenport 28 years ago.

"It means a lot," she said. I didn't think about it until I realized how close I was, and I think I got a little nervous at the end, but I'm super excited to be playing in the WTA Finals, especially in the United States, and qualifying in singles and doubles is definitely a good achievement.

"I had not anticipated this when I set my goals for the year. I'm overjoyed, and I'm hoping to put on a good show there."

Gauff joins Iga Swiatek, Ons Jabeur, her doubles partner Jessica Pegula, and Caroline Garcia in the eight-woman field for the WTA Finals in Fort Worth, Texas, which begin on October 31.

The Guadalajara Open is the final qualifying tournament, with seven women competing for the final three spots.

Number one seed Last year's WTA Finals semi-finalist Paula Badosa had her qualification hopes dashed when she retired due to illness after losing the first set 6-2 to Victoria Azarenka.

Wimbledon champion Elena Rybakina, who was defeated by Pegula 2-6 6-3 7-6 (10-8), is out of the race, as are Belinda Bencic and Liudmila Samsonova, who defeated second seed Aryna Sabalenka 6-4 2-6 6-2 but had other results go against her.

Sabalenka could still qualify, while victories by Veronika Kudermetova, Madison Keys, Danielle Collins, and Jelena Ostapenko kept their hopes alive.