Iga Swiatek clawed her way out of a severe early hole against Marketa Vondrousova at the WTA Finals, then pulled away by displaying a dominant show in the second set to win 7-6(3), 6-0 in round-robin action on Monday. Swiatek, who won her third Grand Slam title at the French Open in June, is ranked No. 2 and has a chance to replace Aryna Sabalenka at No. 1 depending on their outcomes at the season-ending events.

The reigning Wimbledon champion, left-handed Vondrousova, broke in three of Swiatek’s first four service games on the way to a 5-2 lead. The Pole star Swiatek struggled to find her range on the event’s temporary outdoor hard court, which has been criticized by some players and she was responsible for 13 of the match’s first 16 unforced errors.

The Czech player Vondrousova served for the set at 5-2 and 5-4, but Swiatek began to turn things around, scoring 13 of 17 games in a row. Swiatek took a 6-5 lead after a four-game winning streak. The 22-year-old Swiatek took over for good in the tiebreaker at 3-all. To go to set point, she produced a powerful forehand winner, grabbed a service winner, and hit her first ace of the evening, before Vondrousova double-faulted to end it.

Swiatek had won the pair’s last two meetings, including a 7-6 (3), 6-1 quarterfinal win in Cincinnati in August. Vondrousova had two chances to serve out the opening set in that match but failed both times. Swiatek, like that day, escaped in a similar manner. Swiatek fell behind by a double break on this occasion as she battled to find consistent timing against the Czech’s variation. However, two bold return games with the evident purpose of hitting the left-hander paid off.

Swiatek made her move after changing ends with a powerful inside-out forehand strike to decide matters in the tie-break. Her first ace set up three set points two points later. Vondrousova quickly followed with a double fault long.

In surrendering serve to begin set two, the No.6 seed sprayed four unforced errors, including three deep forehands. Swiatek used a 12-point game to consolidate before piling it on as she frequently does as the leader. The match was hers after one hour and forty minutes. Swiatek improved to 18-2 in tour-level matches against lefties in her career, and she is 7-0 (14-0 in sets) this season.