Coco Gauff has been told to improve two key parts of her game by Serena Williams’ former coach, Rick Macci.
The 21-year-old has struggled for form on the WTA Tour since clinching her second Grand Slam title at the French Open in June.
Gauff has failed to reach a single semi-final in the last two months, and suffered a shock first-round exit at Wimbledon last month.
She was beaten in straight sets by the unseeded Dayana Yastremska at the All England Club, while things haven’t got much better recently.
At last week’s Cincinnati Open, Gauff was beaten by Jasmine Paolini in three sets in the quarter-finals.
This came just a week after the US star was knocked out of the Canadian Open in the third round by eventual winner Victoria Mboko.
With the US Open singles draw getting underway on Sunday, Gauff’s preparation for the final major of the year has been far from ideal.
Despite this, however, Macci, who previously coached both Serena and Venus Williams, has insisted the future is still bright for the tennis star, as long as she hones in on two parts of her game.
Taking to X, the American coach stressed that Gauff must iron out her ongoing issues with her serve and forehand.
He wrote: “Coco will be OK as she fights and knows how to play.
“But to ever breathe rare air she has to address the alarming red flare.
“She is at a career crossroad with the 2nd serve and forehand but needs a science based plan.
“This will not magically go away and bubbles up more under extreme pressure that particular day.”
As well as coaching the Williams sisters, Macci also worked with three other number one ranked players in Andy Roddick, Jennifer Capriati and Maria Sharapova.
This isn’t the only time he has highlighted Gauff’s second serve as a key area for improvement.
In a recent interview with tennis365, the 70-year-old claimed Gauff could become a dominant force with a more reliable serve.
He said: “Think about it, her wide serve to the deuce court is one of the best in the world, but then in the same breath, we’re talking about she leads the WTA Tour in double faults.
“So there’s a disconnect.”
He continued: “Then, if that changes, I think not only could Coco become No 1 – which she probably will anyways – I think she could stay there for a long time, because her backbone is better than her backhand and she’s an Olympic sprinter with a racket in her hand.
Macci added: “But to be great, it’s a package, and if this serve could be modified, I have no doubt where she could end up – double digits (Grand Slams) is around the corner for Coco.”
Gauff’s serve has long been highlighted as a weakness in her game, with her numbers significantly behind than her WTA Tour rivals.
Over her last five matches, she has averaged a 9.2 double faults per match.
World number 11 Elena Rybakina comes closest to her here, averaging 4.2 double faults over the same period.
Meanwhile, Gauff has the lowest winning percentage on second serve points over her last five matches, winning just 48.5 per cent of these.
In comparison, Aryna Sabalenka, Iga Swiatek, Jessica Pegula and Elena Rybakina have all averaged over 50 per cent in this category across their last five matches.