A Strategic Shift Just Before the Slam
In a bold and calculated move just days before the 2025 US Open, American tennis star Coco Gauff has hired biomechanics expert Gavin MacMillan—best known for transforming Aryna Sabalenka’s serve—following a string of troubling performances on her own serve. Gauff’s decision comes after a disappointing run at the Cincinnati Open, where she registered an alarming 16 double faults during her loss to Italy’s Jasmine Paolini.
With the spotlight intensifying ahead of her home Grand Slam, the 21-year-old world number three is taking no chances. In an effort to fine-tune her technique and regain confidence, Gauff has parted ways with coach Matt Daly, who had worked closely with her serve and forehand.
What the Change Now?
Gauff’s recent performance issues—particularly her serve—have raised red flags. Although she clinched the French Open title earlier this year, her serve has proven unreliable in recent matches. The final straw came in Cincinnati, and rather than wait until the off-season to make changes, Gauff chose to act immediately.
Despite Daly’s contributions to her game, including helping her lift a Grand Slam trophy, he has now exited her coaching team. In his place steps Gavin MacMillan, a Canadian coach with a reputation for scientifically overhauling players’ technique using biomechanics and anatomical analysis.
Enter Gavin MacMillan: The Biomechanics Mastermind
MacMillan earned widespread recognition for his work with Aryna Sabalenka, whose career was plagued by serving woes until she turned to him. Through detailed anatomical study and biomechanical refinements, MacMillan helped Sabalenka address core technical issues—ranging from weight distribution to shot fluidity and angle optimization.
Under his guidance, Sabalenka transitioned from being a raw top-10 talent to a three-time Grand Slam champion and one of the most dominant players on the WTA Tour.
Now, Gauff is hoping to see a similar transformation.
Technique and Confidence: The Twin Pillars
MacMillan is expected to focus not only on the mechanical elements of Gauff’s serve and forehand but also on the psychological aspects of performance. With limited time before the US Open begins, rebuilding Gauff’s confidence could be just as critical as technical improvements.
In an interview with Performance-Plus Tennis, MacMillan acknowledged the challenges of making significant technical adjustments during the relentless WTA schedule. Nonetheless, he emphasized the importance of targeted, intensive sessions—something Gauff seems to be embracing fully. She has been seen putting in extra hours on the practice courts with MacMillan, even in rainy conditions at Flushing Meadows.
Team Dynamics and the Road Ahead
While MacMillan joins the coaching setup, Jean-Christophe Faurel remains on Gauff’s team, ensuring some continuity as they head into one of the season’s most high-pressure tournaments. This collaborative approach may help balance the introduction of new technical tweaks with Gauff’s existing game structure.
Her opening-round opponent, Ajla Tomljanovic of Australia, is ranked 84th in the world—a potentially manageable start for Gauff. But at the US Open, anything can happen, and Gauff knows the stakes. Having won her first Grand Slam title here two years ago, expectations are sky-high.
Final Thoughts: Risk or Reward?
Tweaking technique just before a major might seem risky, but for a mentally resilient player like Gauff, it could be the catalyst for another deep run in New York. If MacMillan can replicate the magic he worked with Sabalenka, Gauff may yet serve her way to a second Grand Slam title—this time on home soil.