Garbine Muguruza beat Anett Kontaveit 6-3, 7-5 on Wednesday to become the first Spaniard to win the elite season-ending WTA Finals in Guadalajara, Mexico.
Muguruza, the winner of the 2016 French Open and 2017 Wimbledon titles, capped a 2021 campaign that saw her return to the highest level with titles in Dubai and Chicago after three years outside of the top 10.
Muguruza, a former world number one, is projected to end the year at number three in the world.
Kontaveit, whose late-season surge included titles at Moscow and Cluj-Napoca, is projected to reach a career-high ranking of seventh in the world.
Muguruza battled back from a breakdown in the second set, winning the last four games of the match to seal her 10th career title, breaking Kontaveit at love.
She notched her second win of the tournament against Kontaveit, having ended the Estonian's 12-match WTA win streak with a must-have round-robin victory on Sunday.
It was the seventh time in WTA Finals history that round-robin opponents have had a rematch in the final.
"I'd like to congratulate Garbine," Kontaveit said as she accepted her runner-up award. "You've beaten me twice this week, that's just too good."
For Muguruza it was another standout performance in Mexico, where she won back-to-back titles in Monterrey in 2018 and 2019.
The WTA Finals were moved to Guadalajara from Shenzhen, China, because of the coronavirus pandemic.