France's Caroline Garcia claimed the biggest singles title of her career with a straight-set win against Aryna Sabalenka in the season-ending WTA Finals in Texas.

Garcia was ranked outside the top 70 in June but will rise to a career-high number four after winning four titles and reaching the US Open semi-finals.

"It was a great match. I really went for it," said sixth seed Garcia.

"A crazy final, a lot of intensity on every point. Just really proud of the work we did throughout the year. I'm really happy to win my biggest title."

Neither player conceded a break point during a tense first set but two double faults from Sabalenka in the tie-break handed the initiative to Garcia.

She then broke Sabalenka's serve in the first game of the second set and held her own serve after that early breakthrough to take the match.

"Sometimes you are emotional or things don't go your way,"added Garcia, who is the second French player to win the WTA title following Amelie Mauresmo in 2005.

"Sometimes there is a big fight, so you have to find your way through it and that was one of the biggest points I improved. Today one of the most important things was to stay calm and jump on every opportunity."

Sabalenka, who will rise to world number five after reaching the final, said momentarily lapses in concentration at crucial moments cost her the match.

"I just dropped my level for a little bit - on the tie-break and in the first game of the second set," she said.

"The key moments, I dropped my level. That's it."