Coco Gauff made a stunning move right before the US Open, which may already be paying dividends.
On the eve of the final Grand Slam of the year, Gauff split with coach Matt Daly, who had guided her to the French Open title just three months earlier.
Immediately replacing Daly, Gauff hired Gavin MacMillan, a biomechanics expert, who had previously enjoyed success alongside Aryna Sabalenka, fixing her serve.

Reacting to the move, Serena Williams’ former coach Rick Macci suggested hiring MacMillan was a ‘career changer’ for Gauff.
After watching Gauff’s serve improve in the first few days of her and MacMillan’s coaching relationship, Macci is even more impressed.
Rick Macci can already ‘see the difference’ in Coco Gauff’s serve
Playing an exhibition match alongside Andre Agassi during US Open fan week, Gauff’s new-look serve was seen in action for the very first time.
Reacting on X, Macci claimed he could already see positive changes made to the world number three’s serve.
“Just from watching limited video of Coco [Gauff] practicing her serve, major biomechanical modifications have been made, and you can see the difference, as symptoms are magically disappearing,” he said.
“Most of all, she feels it, and when you feel it, you deal it.”
The 70-year-old believes particular progress has been made on Gauff’s second serve, which had troubled her over recent months.
“Watch the difference in Coco and her second serve, especially on the AD court,” said Macci.
“With a new take-back and a sequenced throwing motion, this will trigger a proper counter rotation of the spine, and the toss will naturally follow and deliver more sauce.
“Add in an explosive right arm live wire, her angle will be more acute and the ball will kick eight to 12 inches higher.”

Macci was pleased with Gauff’s serving efforts, but how did she get on in her first ‘match’ with MacMillan as coach?
Who won the exhibition match between Coco Gauff/Andre Agassi and Venus Williams/John McEnroe?
Taking on Venus Williams and John McEnroe in a ten-point tiebreaker, Gauff and Agassi started strongly, taking a 5-0 lead.
Unsurprisingly, the ever-competitive McEnroe wasn’t best pleased to fall down 0-5, as he told Williams they were ‘done being nice’.
Winning three points in a row, McEnroe and Williams reduced the deficit to 3-5, as they continued to entertain the fans on Arthur Ashe Stadium.

Momentum swung back and forth until the two teams were level at 10-10, needing two points to secure victory.
A thunderous forehand from Williams put them within a point of the win, much to the enjoyment of her partner, McEnroe.
When the reliable backhand of Agassi produced a rare unforced error on the return at 10-11, Williams and McEnroe secured the exhibition win.
Not too disappointed with the defeat, Gauff was quick to praise Agassi, who played some fine tennis during the tiebreaker.
“Your ball striking is so good. That is amazing. I don’t think you guys understand how talented you have to be to not play for a while and then play like that,” she said.
Of course, Agassi and McEnroe won’t be competing in the main draw of the 2025 US Open, but Gauff and Williams both will.
But who will they play in their opening matches at this year’s tournament?
Coco Gauff and Venus Williams’ first-round opponents at the US Open
Gauff, the 2023 champion, will begin her campaign against Australia’s Ajla Tomljanovic, who picked up the biggest win of her professional career on Arthur Ashe Stadium a few years ago.
During Serena Williams’ final tournament before retirement, she advanced to the third round in New York, where she met Tomljanovic.
In three sets, Tomljanovic defeated Williams 7-5, 6-7, 6-1, bringing the American’s legendary career to a close.
Now ranked 84th on the WTA Tour, Tomljanovic will be hoping to pick up another big win on Arthur Ashe when she takes on Gauff.
[Venus] Williams will play Czechia’s Karolina Muchova in round one, a former two-time US Open semifinalist.
She’ll likely be a big underdog against the 29-year-old, although it would be dangerous to count the veteran out.
It remains to be seen if Gauff and Williams will win their opening matches, but it will certainly be worth tuning in for when the tournament begins on Sunday, August 24.
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