Preview: Marta Kostyuk vs. Jessica Pegula - WTA Finals prediction, form, head-to-head

Seeking her first WTA Finals victory, Marta Kostyuk faces Jessica Pegula in her second match of the tournament in Group 1.

The Ukrainian lost her opener to Linda Noskova 2-6 4-6, while Pegula lost a three-set outing versus Coco Gauff 4-6 7-6 (7-5) 2-6.

Match preview

She was thrust into the spotlight at the last moment, and Kostyuk looked at times unprepared and overwhelmed in her opener.

The replacement for 2025 champion Elena Rybakina was only called up on Saturday afternoon after the latter pulled out with an injury.

Kostyuk had a first serve percentage of only 38% on Sunday, while conceding four break points as she was beaten decisively in straight sets.

She has now lost her last two singles outings at Indian Wells in straight sets, with Rybakina beating her 4-6 4-6 in the round of 32 at the Indian Wells Open in March.

Her losing run is now at four consecutive singles matches, with Kostyuk's last singles victory coming in a walkover at the Guadalajara Open against Taylor Townsend in September.

For the year, she has saved over 60% of her break points, while converting just under 50% of her opportunities across all surfaces.

She made a valiant comeback, but in the end Jessica Pegula began to fade in the third set against her American counterpart on Sunday.

In a match that swung back and forth multiple times throughout the opening two sets, Pegula kept pace with Gauff for a long stretch, winning the only tiebreak between them.

Errors proved costly in her opener, with Pegula committing six double faults and conceding seven break points.

On Tuesday, Pegula will seek her first victory in the group stage of this tournament since beating Jasmine Paolini in straight sets 6-2 6-3 last year.

In her opener, Pegula captured 65 service points, but only won 47% of her second serves, with Gauff winning 56% of hers.

In 2026, Pegula has won over 40% of her return points, but under 40% of her return games across all surfaces for the year.

Tournament so far

Marta Kostyuk:

First match: vs. Linda Noskova 2-6 4-6

Jessica Pegula:

First match: vs. Coco Gauff 4-6 7-6 (7-5) 6-2).

Head To Head

CIncinnati Open (2022) - Round of 32: Pegula wins 6-7 6-1 6-2

Australian Open (2023) - Round of 32: Pegula wins 6-0 6-2

San Diego Open (2024) - Semi-finals: Kostyuk wins 7-6 6-1

Miami Open (2025) - Round of 16: Pegula wins 6-2 6-3

Beijing Open (2025) - Round of 16: Pegula wins 6-3 6-7 6-1

Brisbane Open (2026) - Semi-finals: Kostyuk wins 6-0 6-3

Madrid Open (2026) - Round of 32: Kostyuk wins 6-1 6-4

In their first meeting, Pegula came back from a set down to win in Cincinnati, hitting 76% of her first serves to take the match.

When they first met in a major tournament the following year, Kostyuk committed eight double faults, with Pegula converting six break points.

Kostyuk got her first win over Pegula in San Diego in 2024, hitting three aces while winning 72% of her first serves.

In Miami in 2025, Pegula beat Kostyuk again, winning 90% of her second serves to advance in straight sets.

The next time they faced off in Beijing, it was a close three-set affair which Pegula won, thanks to her eight break points converted.

In Australia earlier this year, Kostyuk came out on top, converting four break points while not conceding a single ace to Pegula.

Kostyuk made it two in a row in Madrid, registering five aces and winning 74% of her second serves to advance.

We say: Kostyuk to win in three sets

While Kostyuk has little experience at this event, she has good momentum against Pegula, and we believe the American’s stamina could be an issue against the Ukrainian, who is used to longer rallies.