Świątek defeated France's Caroline Garcia 6-3, 6-2 in Texas.

However, there is still a chance for Garcia to reach the knockout stage if she beats Russian Daria Kasatkina on Saturday.

Świątek has now recorded 47 straight-set wins on the Tour this year.

Her victory over Garcia means the Pole is only the second player to ensure progress from the round robin stage of the season finale, after Greek world number five Maria Sakkari.

"For sure, I am trying to focus more," Swiatek said after the win.

"It’s my goal in this tournament, because in San Diego I felt like I needed to lose on set to get to a different level of focus - maybe because I was tired.

"But here, I feel like I can just give it all in.

"It’s the last tournament of the season and I have nothing to lose.

"I don’t have to worry about what I’m going to do next.

"For sure, I’m committed 100 percent physically and mentally as well."

Meanwhile, Kasatkina, playing as a neutral, beat Coco Gauff 7-6, 6-3 to send the American to bottom of the Tracy Austin Group.

"It was tough," Kasatkina said.

"I was nervous at the beginning. ... With the rhythm of the match, nerves disappear a little bit and start to be better.

"So I'm really happy to be in the next round, still alive."