Rennae Stubbs pinpoints improvements in Coco Gauff's serve after American's nail-biting first round victory at US Open

American tennis prodigy Coco Gauff was involved in a thrilling contest during the first round at the US Open, requiring three sets to take down Ajla Tomljanovic. Gauff's performance was subsequently analyzed by many in the tennis community, with former player Rennae Stubbs pointing out some differences in the World No.3's serve.

The 2023 champion has been struggling with her serve over the last two years, having led the WTA in double faults during the 2024 season. Gauff's serving woes prompted her to part ways with her former coach and bring on a serve specialist prior to the US Open.

With the world watching on Tuesday night, Gauff was able to overcome Tomljanovic in a 6-4 6-7(2) 7-5 victory. Although the American hit 10 double faults, some noted improvements in her form and technique when compared to the last few weeks.

Retired doubles specialist Rennae Stubbs was one of many to analyze Gauff's new serve. The Australian coached WTA legend Serena Williams during the latter's final years on tour, and gave her opinion on how Gauff had modified her service motion and technique.

Gauff's toss and contact point are different, says Stubbs

As Gauff battled Tomljanovic on Arthur Ashe stadium, Stubbs updated fans with some live commentary on social media during the match. The retired WTA star highlighted how much Gauff's serve had changed when analyzed against her previous service motion.

"Coco doing a better job of getting the ball toss behind her head for the kick serve," wrote Stubbs on Twitter. "Obviously trying to manage that and get better shape on it to clear the net. Hitting 11am and not 1pm on the ball. When she tosses it too far to the right 1pm/2pm it drags her head down."

Furthermore, Stubbs gave high praise to Tomljanovic, who was very close to causing an upset on Tuesday night. The 32-year old Aussie broke American hearts three years ago at Flushing Meadows, who she defeated Serena Williams in the 23-time Grand Slam champion's final match on tour.

"Let’s not forget, this match for @CocoGauff is not an easy one against @Ajlatom!" wrote Stubbs. "Ajla at her best can beat anyone. Hasn’t had the year she has wanted to but she’s super capable of playing outstanding tennis. We all remember the match against Serena @usopen on this same court."

Gauff will take on Croatian Donna Vekic in the second round, with the American winning their most recent encounter at the United Cup earlier this year. However, Vekic defeated Gauff at the Paris Olympics last summer.