The world No.118, who flew up the rankings in 2024 after starting the year 684th, ousted 53-ranked Olga Danilovic 6-2 6-3 in the opening round of the Hobart International on Tuesday.
It was just her third WTA tour level win and the most impressive by ranking.
3rd win on the Hologic WTA Tour 💜— wta (@WTA) Maya Joint with a solid showing, picking up the 6-2, 6-3 win over Danilovic!#HobartTennis pic.twitter.com/6ceCI1XH9PJanuary 7, 2025
Joint, who was born in the US, has started the year with confidence, making the second round of Brisbane last week where she took a set off former world No.1 Victoria Azarenka.
"It feels great. It feels really good that it wasn't just a one-time, two-time fluke - that I could do it again," she said.
"(Brisbane) helped me feel that I was at that level and I tried to take confidence from it. I knew I didn't really have any pressure on me."
Joint appeared more at home in Hobart's windy conditions, breaking Danilovic in the opening game and in the final game to seal the win.
"Everything seemed to work. I think I played the conditions pretty well, with the wind," she said.
"I was just trying to have big margins and extra spin on the ball, more footwork."
Joint, who will make her maiden Australian Open main draw appearance via a wildcard, said cards were on the table post-game.
"My team and I play a lot of cards, especially Monopoly Deal. We started a season 2025 tally and I'm losing," she said.
Joint will face fourth seed Magda Linette for a spot in the Hobart quarter-finals.
She is one of two Australians in the Hobart singles field, with Daria Saville to meet third-seeded American Amanda Anisimova on Tuesday night.
In other round-one results, former world No.3 and 2017 US Open champion Sloane Stephens' poor run of form continued with a 7-5 6-1 loss to No.91 Ann Li.
The 31-year-old Stephens, whose ranking has fallen to No.84, has lost eight matches in a row with her last success coming at Wimbledon.
Li will meet top seed Dayana Yastremska, who outlasted American Katie Volynets 2-6 6-4 6-1 in two hours.
It was better news for Stephens' countrywoman and fellow grand slam winner Sofia Kenin, who rallied to beat fifth seed Lulu Sun 4-6 6-3 6-3.
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