Emma Raducanu suffered her worst-ever result at Indian Wells yesterday, crashing out in the first round with a disappointing 6-3 6-2 defeat to Japan's Moyuka Uchijima.
The British No. 2 initially took a promising 2-0 lead but quickly surrendered her advantage.
This marks an unwelcome milestone for the 22-year-old, who had never previously lost in the opening round of the prestigious Californian tournament.
The defeat comes as a significant setback during her trial with new coach Vlado Platenik.
Emma Raducanu was beaten with ease in the first round at Indian Wells
Reuters
Raducanu's promising start quickly unravelled as she lost four consecutive games after establishing her early lead.
Despite briefly getting back on serve, the world No. 52 Uchijima broke again to secure the first set.
The second set followed a similar pattern, with the Japanese player breaking immediately and maintaining control throughout.
Uchijima's victory sets up a second-round clash with third seed Coco Gauff.
For Raducanu, ranked 55th in the world, it was a performance well below her capabilities at what she has previously described as one of her "favourite tournaments".
This match marked Raducanu's return to competition following a distressing incident in Dubai last month, where a stalker appeared at her second-round match, leaving her "distraught".
The British star took time away from tennis before deciding to compete at Indian Wells, with extra security measures in place.
It was also her first tournament under the guidance of Slovakian coach Platenik, whom she recently began working with on a trial basis.
The partnership's debut outing has unfortunately ended in disappointment for the former US Open champion.
Despite the disappointing result, there were some positive signs in the new coaching relationship.
Sky Sports commentator and former player Naomi Broady noted the effective communication between Raducanu and Platenik.
Emma Raducanu was playing her first match since her stalker hell in Dubai
Reuters
"Even though it is a new relationship, you can see the reaction from Raducanu there after she's missed," Broady observed.
"Immediately looking up to the coach, wanting feedback. Coach is giving it. Good communication."
This rapport suggests potential for the partnership, despite the challenging start.
Raducanu had opportunities to regain momentum in the second set, earning three break-back points during a marathon game.
However, she failed to convert any of these crucial chances, allowing Uchijima to extend her advantage.
The missed opportunities appeared to affect Raducanu mentally as her performance deteriorated further.
Facing three break points in her subsequent service game, the Brit double-faulted at the worst possible moment.
This error effectively sealed her fate, giving Uchijima the chance to serve out the match comfortably.
Raducanu is expected to compete at the Miami Open later this month, though she will be hoping for a significantly improved performance.
It remains unclear whether she will continue her trial with Platenik following this early exit at their first tournament together.
The British star will need to quickly regroup and rebuild confidence after this setback if she hopes to make an impact in Miami.
Her team will undoubtedly be reviewing what went wrong in California before making decisions about her coaching situation.