At the 2025 WTA Finals in Riyadh, Coco Gauff finally looked like herself again. The 20-year-old American beat Italy’s Jasmine Paolini 6-3, 6-2 to earn her first win of the group stage and keep her semifinal hopes alive. But more importantly, she showed real progress in the one area that has tested her for over a year: her serve.

This time, Gauff hit only three double faults. That’s a major step forward after her shaky opening match against Jessica Pegula. Her movements were sharp, her backhand steady, and she played with a purpose that had been missing just a few days earlier. Paolini wasn’t at her best physically, but Gauff didn’t waste the opportunity to reset her campaign. After the match, Gauff was asked how happy she was after winning. “Yeah, I’m really happy with how I played today  definitely a turnaround from my first match,” she said.

The interviewer then asked how she managed to make such a quick turnaround. In her first match of the tournament against Pegula, Gauff’s serve was her downfall. She hit 17 double faults, won just 28 percent of her second-serve points, and landed only about 57 percent of her first serves. The errors put her under constant pressure, leading to a 6-3, 6-7(4), 6-2 defeat in the group stage.

Reflecting on that, Gauff explained, “I was just trying to play relaxed, and you know, I played a debut where I lost all three matches, so I was determined not to make that a repeat of that.” The match stats show she won ~76.9% of her total service points.

Coco Gauff further added, “So yeah, I knew that today’s one was important to keep myself in the tournament. Yeah, if I lost, I would’ve been out, so yeah.”Her answer said a lot about where she is mentally. Gauff’s serve has been both a strength and a weakness during the last 12 months.

Her tendency to double fault last season and this season was frequent, and opponents regularly attacked her second serve. Her toss and timing were too erratic, resulting in tense shoulders and rushed motion. However, by the middle of 2025, things had begun to improve.

That changes began during the US Open after bringing on Gavin MacMillan, though inconsistency still appeared under pressure. Even now, she ranks lower among the top 50 players in points won on second serve. Yet in Riyadh, the progress was clear. When asked what she was happiest with, Coco Gauff smiled. “Definitely my serve,” she said.

“I thought I served smart. I think overall my return and everything was solid. I don’t think Jasmine was 100 percent today, so I’d like to give her my well wishes in her next few matches. Playing singles and doubles is not easy.” For Gauff, this victory was about much more than staying in contention, it was proof that her hard work off the court was finally beginning to show.

The fix behind Coco Gauff’s serve

Coco Gauff’s serve has always been one of her biggest weapons and one of her biggest struggles. According to Tennis Abstract, Gauff had the highest double-fault rate among the WTA Top 50 players that year at 9.9%, far ahead of others like Amanda Anisimova, who stood at 6.2%. She realized it was time for a change in 2025 after a string of difficult games that were full of double faults, including 23 in a loss to Danielle Collins in Montreal.

Coco Gauff made a significant decision just before the US Open: she hired biomechanics specialist Gavin MacMillan, parting ways with coach, Matt Daly. The move came at a risky time, but Gauff said she was mentally exhausted from battling the same issue over and over.

As she puts it, “It was, like, a very sudden decision,..Gavin became available. I just felt this was the best decision for my game, and I had to go with what I was feeling.” The arrival of MacMillan marked the beginning of something new, a fix for her confidence as well as her serve.

Known for assisting Aryna Sabalenka in resolving her own serving issues, MacMillan concentrated on making Gauff’s motion simpler. He taught her to keep her head steady throughout the shot and worked on her follow-through, rhythm, and knee bend. Her previous serve was too jerky and tense. Power through flow, not force, was the new objective, and it was smooth and repeatable. Instead of tension, he wanted her to serve with trust. It wasn’t easy at first.

The new movement brought about inconsistency. At the US Open, she shed tears when she won the second round against Donna Vekic and subsequently lost the fourth round to Naomi Osaka. Yet as the weeks went by, the difference began to appear.

Her serves grew more stable (Gauff became steadier), her second serve more reliable, and her number of double faults decreased significantly. What was once a weakness started becoming a strength, as she even won the Wuhan Open. But improvement is all about patience, even when the old mistakes creep back in.

Coco Gauff has a stronger, more confident serve now than ever, now that MacMillan is guiding her. And Wuhan came at the perfect time, giving her a major confidence booster going to the WTA Finals. It is a work in progress, but she has built it back to the ground and above all, she has learned to trust it.