After starting the 2026 season as Australian tennis's new golden girl, Joint endured a horror stretch of 13 losses in 14 matches, including 10 straight first-round exits between the Australian and French Opens.
The 20-year-old slumped from a career-high No.28 in the world to 87th and looked headed towards spiralling out of the top 100.
But the US-born starlet regained her mojo with an eye-catching victory over Williams at Wimbledon, Joint sending arguably women's tennis's all-time greatest abruptly back into retirement with a Centre Court ambush at the All England Club.
Joint hasn't looked back, winning eight matches in a refreshing turnaround to set up a second-round US Open date with world No.9 Elina Svitolina on Wednesday (Thursday AEST).
"My match against Serena at Wimbledon flipped a switch," Joint told AAP after her rousing three-set first-round win over former world No.12 Liudmila Samsonova.
"I got the confidence back that I could win matches and get through tough matches as well."
Joint has now reached at least the second round in New York for three straight years, including the last 32 as a teenage debutant in 2024.
"I really like the energy of the crowd," she said.
"It's a fun place to play. The stands are always packed and it makes playing here special.
"I also grew up in the States, so it feels like a second home slam. I have a lot of friends that come and watch me, which is nice."
Projected to return to the world's top 70 at least, Joint is convinced she can challenge Svitolina to make the last 32 for a second time at Flushing Meadows.
"I've never played against her. She's having a great year this year and is one of the top players, so I'm excited to see how my game matches up against hers.
"I'll try and draw on the match I just played because I'd never beaten her (Samsonova) before either, so I came in as the underdog and I had to problem solve it and find a way through.
"I took a lot of confidence from that match to get through really good opponents, so I think I have a chance against Elina."
Fellow Australians Kim Birrell and Taylah Preston will also be chasing third-round berths on Wednesday (Thursday AEST).
Preston fancies her chances against American doubles ace Taylor Townsend, while Birrell takes on Russian Ekaterina Alexandrova believing she can also topple the Russian seed after taking down world No.5 and 2024 US Open runner-up Jessica Pegula at the French Open.
"She's obviously a great player, a big hitter, and we have played just once in the past and it was quite a close match," Birrell said.
"We only just practised recently, so I'm aware of her game style and I'm going to have to play well, but I'll definitely take some of the belief that I've gained throughout the year and playing these types of matches at slams.
"I'm excited. I've been the underdog quite a lot of times and it's a fun place to be in, so I know that feeling and I know that I can play those matches and come out on top.
"I'm looking forward to the challenge."
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