The match lasted two hours and 39 minutes, with Gauff demonstrating resilience to overcome her compatriot in the opening group stage fixture. Gauff, the 2024 champion, had not competed in a tournament since the China Open in early October.

Gauff recovered from a 5-1 deficit in the second set to force a tie-break, though Pegula ultimately levelled the match. Gauff regained control in the deciding set, winning the first three games and maintaining her momentum to close out the victory.

Reflecting on the performance, Gauff said she was proud of her ability to compete at a high level despite a lack of recent match preparation. She noted that the physical intensity of the contest left her needing to replace her footwear.

In the other Group One match, Czech player Linda Noskova defeated Marta Kostyuk 6-2, 6-4. Kostyuk was a late addition to the tournament field following the withdrawal of world number one Elena Rybakina, who pulled out on Saturday due to illness.

The WTA Finals feature the top eight players of the season competing in a round-robin format across two groups. The top two players from each group will advance to the semi-finals, with the championship match scheduled for next Sunday.

Gauff is set to face Noskova in her next group match, while Pegula will take on Kostyuk. The tournament, which features the world's elite, concludes with the final on 15 November.