It was fun while it lasted. Coco Gauff’s nine-match winning streak was ended in an extraordinary 1-6 6-4 6-4 semi-final defeat to Aryna Sabalenka at the Wuhan Open. The 20-year-old came flying out of the blocks and was a set and 4-2 up before crumbling under the weight of familiar service woes. The 2023 U.S. Open champion coughed up no less than 21 double faults in a disturbing loss that is in danger of knocking over the building blocks that were being laid by new coach Matt Daly.

Those are the basic facts. What lies beneath the fundamental technical collapse of a Grand Slam winner is another matter. After winning the China Open a week ago, Gauff was enjoying the “bounce” of new man Daly’s ideas. She hinted at a few adjustments that were working just fine. “I don’t want to give too much of what’s going on, but there are changes happening. I’ve been playing with them since Beijing,” said the world No.4 after her win over Magda Linette.

The grip on her forehand was touted to be one of those definitive alterations. Taking apart or tinkering with what came naturally needs a strong mind to see it through when faced with the very best in the world. After all, Sabalenka is now 16-0 at Wuhan having won in 2018 and 2019.

Whatever worked in the Chinese capital got lost in translation on Saturday. This was a return to the nightmare of the Emma Navarro match at Flushing Meadows when Gauff coughed up 19 double faults. She went two ‘better’ here. There was no sign of the distress to come when she stormed into a 5-0 lead inside 20 minutes against a subdued first seed. The Belarusian couldn’t control her returns when her opponent managed to get the first shot in play.

The second set was a huge mess of contradictions and zigzag momentum shifts. There were five breaks in a row to start with before the rain briefly came to give respite to an out of sorts Sabalenka as the roof closed. The momentum shifted as Gauff’s service disintegrated into a case of just getting the ball in play. One game included four double faults but somehow she won it. Resilience is not a problem.

If Gauff is to challenge properly for the majors she will need to stablilize the fault lines that have tripped up this mini resurgence. It doesn’t seem possible to go from serving no double faults in a fine win over Marta Kostyuk a few days ago to seven in the quarterfinal and then triple that against the current U.S .Open champion.

When she gave an almost flawless performance against Karolina Muchova to claim the Beijing title, Gauff said she just woke up and felt that it would be her day. What she needs to develop is a more surefire way of not breaking down in public view when the mechanics and the mindset are not in synchronicity. “A lot of times people forget that I’m still in the developmental phase of my career… Most of the people doing well are 25 and older in the Top 10, maybe with the exception of Iga,” she said last week. That’s true enough, but such errors shouldn’t happen at Championship level. Even on a bad day.

“I always knew I wanted to win multiple. The only thing I will try to remember from [the US Open] is just the way that I won. It wasn’t my best tennis. It was more the mental fire,” she remarked at the beginning of this year. Ultimately, Gauff will have to back this with a consistent skillset. When Sabalenka mentioned that she was waiting for her opponent to drop her level, it sounded like an expectation rather than a hope.

Gauff has expressed her desire to win double digit Grand Slams. She will try to minimize the impact of that one loss in the last ten by remembering the solid work of the last fortnight during a good Asian swing. The end of year push was looking good until the latest service splutter.

The honeymoon period is over with Daly and the hard work now begins. Changing coaches is not news these days nor is it the answer when there are fundamentals missing. Finding the base to impose her game on others will see more painful days ahead. Multiple major champions don’t lose so many cheap points.