Teenager Linda Noskova pulled off a huge upset to knock world number one Iga Swiatek out of the Australian Open in the third round.
Swiatek had dug herself out a major hole in the second round against Danielle Collins but she was unable to repeat the trick against Noskova, going down 3-6 6-3 6-4.
The never-ending production line of Czech female talent is one of the wonders of tennis, and 19-year-old Noskova is at the head of a new generation.
Ranked 50 but set to rise rapidly, she showed superb maturity to turn the match around after losing the first set.
Noskova began to outhit her illustrious rival through the second set and into the third, where a break of serve for 5-3 proved the crucial moment.
She looked stunned after converting her first match point, and said: "I'm speechless, obviously.
"I knew it's going to be an amazing match with the world number one and such a player. I didn't really think it would end up like this but I'm just really glad to get through this round."
She is the first teenager to beat a world number one at the Australian Open since Amelie Mauresmo defeated Lindsay Davenport in 1999.
Noskova hit 10 aces in a tally of 35 winners, with a forehand return drilled over the baseline from Swiatek sealing her fate.
It is only the second time in the last 13 grand slam tournaments that Swiatek has failed to make it beyond the third round but it represents a second early exit in a row after she lost in the fourth round of the US Open.
She is guaranteed to hang onto top spot in the rankings, though, with her nearest challenger Aryna Sabalenka unable to gain points having won the tournament last year.
Noskova next plays 19th seed Elina Svitolina (above), who was a comfortable 6-2 6-3 winner over Viktorija Golubic and will fancy her chances of reaching a first grand slam final.
So, too, will 12th seed Zheng Qinwen, who is the highest-ranked player left in the top half and is making waves, 10 years on from Li Na's historic triumph.
Zheng needed two hours and 40 minutes to make it past countrywoman Wang Yafan 6-4 2-6 7-6 (10-8) on Friday as China took centre stage in the day session on Rod Laver.
In the last 16, she will take on Oceane Dodin, who defeated fellow unseeded French player Clara Burel 6-2 6-4 to reach the fourth round at a slam for the first time.
One of Zheng, Dodin, 26th seed Jasmine Paolini and Russian Anna Kalinskaya is guaranteed to make a first slam semi-final.
Paolini ended the run of Anna Blinkova, who knocked out Elena Rybakina in round two, while Kalinskaya beat former finalist Sloane Stephens 6-7 (8-10) 6-1 6-4.
It is turning into an excellent tournament for Ukraine, with Dayana Yastremska joining Svitolina and Marta Kostyuk in the last 16, thanks to a 6-2 2-6 6-1 upset of 27th seed Emma Navarro.
She next faces two-time former champion Victoria Azarenka, who is again looking strong in Melbourne and came from 2-5 down in the second set to beat Jelena Ostapenko 6-1 7-5.
