Paula Badosa is off to a stellar start…

The 23-year-old Spanish professional tennis player, competing in her first-ever WTA Finals, started off slowly but won 10 games in a row to upset top-seeded Aryna Sabalenka 6-4, 6-0 on Thursday in their opening match at the WTA Finals.

Sabalenka, the world´s No. 2-ranked player, dominated early in the match to take a 4-2 lead, but Badosa recovered and won four games in a row to win the first set and then controlled the second with three breaks.

“I played pretty good, the conditions here are tough to play, but I played an amazing match. I knew I had to play like this to beat her,” Badosa said.

Sabalenka, who won titles in Abu Dhabi and Madrid this season, is the first seed in Mexico because world No. 1 Ash Barty of Australia decided not to defend her WTA Finals title due to continuing COVID-19 travel and quarantine restrictions.

Barty had to undergo two weeks of quarantine when she returned to her Brisbane home in September after the US Open and did not want to do the same again traveling to Mexico.

“I am really disappointed of myself and this match, but hopefully I can bring myself back,” Sabalenka said.

Badosa is having a breakthrough season after starting the year ranked 70th. She will next play Maria Sakkari, who used her strong first serve to extend her dominance over former French Open champoin Iga Swiatek with a 6-2, 6-4 win earlier Thursday.

“My life has changed so much and very fast, I have so much more stress now with a lot of eyes on me,” Badosa said. “The ceiling is high for me, I have always dream big, I want to play in this type of tournaments to play against the best and being challenged every day.”

All of the players are having to adjust their game to the nearly 5,000-feet altitude of Guadalajara, Mexico’s second-largest city.

The tournament, which was canceled last year because of the COVID-19 pandemic, features a round-robin group stage before the semifinals.

The WTA Finals are being played in Guadalajara for this year only, with the event scheduled to return to Shenzhen, China, in 2022.