NO. 4 seed Coco Gauff opened the WTA Finals with a stellar 6-4, 6-7 (5), 6-2 victory over No. 5 seed and fellow American Jessica Pegula on Sunday in Indian Wells, Calif.

Gauff saved 7 of 11 break points while breaking Pegula's serve seven times in 16 chances. Pegula saved one match point in the 12th game of the second set on her way to forcing the tiebreaker, but Gauff won the first three games of the decisive set and never looked back.

Gauff earned a valuable victory to kick off the round-robin group stage. Gauff is the highest-seeded player in Group 1 following the withdrawal of World No. 1 Elena Rybakina of Kazakhstan due to a viral illness.

Rybakina's replacement, Ukraine's Marta Kostyuk, carries a No. 9 seed and faced Czech eighth seed Linda Noskova in the day's other match. Noskova cruised 6-2, 6-4, converting all four of her opportunities to break Kostyuk's serve.