The Sydney-born Konta, who came through a draining three-setter in the fourth round, recovered to oust Zhang 6-4, 6-1 and set up a last-four clash against German seventh seed Angelique Kerber.
Kerber stunned two-time champion Victoria Azarenka 6-3, 7-5 in the match preceding Konta’s on Rod Laver Arena.
The 24-year-old Konta, who has blossomed in the last year, had never been beyond the fourth round at a Slam before but she now equals fellow Brits Virginia Wade (1972, en route to the title) and Sue Barker (1975 and 1977) in making the Melbourne semis.
In her Australian Open debut, she also became the first British woman to reach a semi-final at any of the Grand Slam tournament since since Jo Durie at the US Open in 1983.
“She didn’t make it easy,” an ecstatic Konta said of Zhang. “I’m happy. I was able to fight every single point.
“I didn’t put anything on this match, I just wanted to come out and play the best level that I could, and give the best entertainment I could.”
This time last year Konta was ranked 147 and fell in qualifying for Melbourne Park, but she has since risen 100 places, crediting her transformation with a new mental attitude.
She stunned eighth seed Venus Williams in the opening round and has stayed on a roll ever since, having more finesse and power than Zhang.
The Chinese star, who had lost all 14 of her previous Grand Slam matches before this year’s tournament, was responsible for the demise of second seed Simona Halep and injured 15th seed Madison Keys. But the 27-year-old was always playing catch-up to Konta.
