In what was seen as a claycourt dress rehearsal after the Aussie pair had also been drawn to meet each other in the first round at Roland Garros, 19-year-old Joint came out on top in her last-four encounter with Ajla Tomljanovic at the Morocco Open in Rabat on Friday.
Joint was just beginning to assert her authority in the match by taking the first set 6-4 but world No.79 Tomljanovic's withdrawal at the end of the stanza still came as a bit of surprise to her opponent and the crowd.
"I mean, it's never the way you want to win, Ajla's a good friend," said Joint, after defeating her Billie Jean King Cup teammate.
"But we we play each other first round in Roland Garros next week, so we'll be able to try this again -- but I hope that she can get better quickly.
"It's very difficult (playing against a fellow Australian). I was definitely feeling a bit nervous having to play her, but we're both professionals. We both have good game styles, so I knew it'd be a good match, competitive.
"I started off pretty well, really feeling my shots, and she was coming back and testing me, but I'm glad that I was able to pull it out in the end of the set."
It was a generation game largely played on Joint's racquet over the 39 minutes as the youngster dominated the early stages against the experienced 32-year-old, moving into a 3-0 lead for the loss of just two points with her crisp forehand proving hugely effective.
Tomljanovic roared back to level the scores but folded near the end of the set as Joint applied the pressure, grabbing a set point from the older player's poorly-executed drop shot and then sealing the stanza with a fine service return that her opponent couldn't retrieve.
It's another milestone for the American-born, Brisbane-based Joint, who threw in her lot with her squash-playing dad's home country of Australia a couple of years ago and has risen inexorably, now to the verge of the world's top 50.
There is only one other teenager in the world's top 100 ranked higher than Joint - 18-year-old Russian phenomenon Mirra Andreeva.
Joint was 684 in the world at the start of last year, rose to 116 throughout 2024 and, having now come through her second WTA semi-final with a win, she's guaranteed to be No.60 next week or even as high as 53 if she beats either Colombia's Camila Osorio or Romania's Jaqueline Cristian in the final.
