The Moscow-born Kazakh bounced back from early serving issues to down the second seed 7-5, 6-1 and will meet either Jessica Pegula or Amanda Anisimova for a place in Saturday’s final.
Rybakina has made the Melbourne final once before, in 2023 when she lost in three tough sets to Aryna Sabalenka.
She had not been past the last eight in Melbourne since then.
But the 2022 Wimbledon champion has been one of the tour’s form players in recent months, now winning 18 of her last 19 matches with her only loss in the Brisbane quarter-finals this month.
She is into her fourth career Slam semi and first since Wimbledon in 2024.
“Really pleased with the win,” said the 26-year-old.
“We know each other pretty well and I was just trying to stay aggressive.
“I feel like in the first set for both of us, the first serve was not really working, so just trying to step in on the second serve, put pressure on each other.
“I think in the second set I just started to play more freely and served better.”
Defeat denied Swiatek a career Grand Slam of all four majors.
She has won four French Opens, the US Open and Wimbledon, but a title at Melbourne Park remains elusive.
Swiatek and Rybakina had met 11 times before, including five last season, with the Pole holding a narrow 6-5 edge.
But Rybakina won the last encounter at the WTA Finals in Riyadh.
Swiatek forged a break on Rybakina’s opening serve, with the Kazakh getting only one of her first serves in, but she struck back immediately to keep the match level.
Rybakina’s serve was misfiring and the Pole worked another three break points in the next game, but all were saved as the fifth seed hung on.
The Kazakh made some adjustments and her serve finally started to hit the mark.
There was little to split them until Swiatek served to stay in the set at 5-6 with Rybakina going for her shots and converted on the second set-point opportunity.
The writing was on the wall for Swiatek with Rybakina winning her last 21 matches after taking the first set, and she pounced early with a sizzling forehand return earning a break to love.
She consolidated for 3-0 and when two straight aces made it 4-1 there was no way back for the Pole. (AFP)
