World no. 133 Zhang Shuai hadn't won a grand slam match in 14 attempts before Tuesday night. That all changed when she met the number two seed Simona Halep.
The Chinese player shocked last year's US Open semi-finalist in straight sets 6-4 6-3, and she broke down in tears after her remarkable upset win.
Zhang, who contested the women's doubles at the 2012 London Olympics with Li Na, thanked the 2014 Australian Open champion during an emotional post-match interview.
"Li Na is a great player and gave me a lot of help so thank you to her," Zhang said.
"Yesterday I saw her ... she's always helping the young players. "I want to thank my coach and my parents. Thank you everybody for supporting me.
"Today is the best moment of my career ... beating a top-two player. I'm so happy, so excited."
The crowd gave her a tremendous ovation, clearly moved by her performance, and she had plenty of support from other players on Twitter, who admitted they too were overcome with emotion.
Zhang saved nine break points in the contest, which lasted an hour and 18 minutes.
Romanian Halep, who has been struggling with a niggling achilles injury, had no answers to Zhang's dominant baseline game on Margaret Court Arena.
The odds had been heavily stacked in Halep's favour with Zhang boasting the worst record of any top 300 player.
But she was a different player on Margaret Court Arena, punishing the Romanian's scrappy service game while dominating at the net and from the baseline.
Few would given her any hope as the two walked out on court, but Halep didn't know what hit her as Zhang raced to a 4-0 lead.
The second seed finally got a break in the fifth game and looked to be clawing herself back into the match at 2-4, but she lost focus as sweat poured off her and Zhang pounced again to take the set.
Halep appeared to regain her composure as the second set unfolded, taking a 3-1 lead before Zhang again stepped up her game, reeling off a forehand winner to secure the biggest scalp of her career.
It was the second massive upset in the space of a couple of hours after Rafael Nadal was sent packing by compatriot Fernando Verdasco.
It was a huge setback for Halep, who is enjoying her highest ever ranking after a stellar 2015 in which she won titles at Shenzhen, Dubai and Indian Wells, raking in more than US$4.5 million in prize money.
She made clear ahead of the tournament that the ultimate goal was Grand Slam glory, with that dream now on hold.
Shuai Zhang is making me all teary eyed being all emotional after her win over Halep. Her first grand slam win in 15 attempts #AusOpen— Heather Watson (@HeatherWatson92) January 19, 2016
My god!Zhang Shuai,it was so emotional??Congrats.Long wait,but such a big win worth it??...@zhangshuai121— Elena Vesnina (@EVesnina001) January 19, 2016
Zhang Shuai's story is amazing. Contemplated retiring after US Open, brought parents to #AusOpen thinking it might be her last tournament.— Ben Rothenberg (@BenRothenberg) January 19, 2016
ZHANG'S PATH TO OPEN BOILOVER:
* 2008: loses on grand slam debut in New York
* 2010: loses at French Open
* 2011: loses at all four slams
* 2012: loses at Melbourne Park and Roland Garros
* 2014: loses at all four slams
* 2015: loses at Melbourne Park and Roland Garros
- News.com.au with AFP