Halep had not only won her last 11 matches in a row, a run that took her to her first two WTA titles at Nürnberg and 's-Hertogenbosch the last two weeks and into the second round this week, she had also won her only previous encounter with Li - needless to say, the match was a major upset alert.
And though Li cruised through the first set, 6-2, things looked headed for disaster as Halep stormed out to a 5-0 lead in the second set - but the No.6-seeded Li settled down again, getting a game on the board before the set was gone, 6-1, then blazing through the third set at love to win, 62 16 60.
"I would like to say welcome to the crazy women's tennis tour," Li joked at her post-match press conference. "I knew if I didn't wake up in the third set, I would be out of the tournament. I told myself to wake up. I had to do better than the second set. So I just fought for every single point out there."
Was Li affected at all by 'Wimblegeddon', as the day before had been dubbed, with so many top names going out? "I was feeling a little bit bad for Wimbledon, because so many big stars were going out of the tournament, and also so many pulled out with injury. But at the same time I really didn't want to be the next one. So last night and this morning I really prepared what I should do on the court today."
"I played her at the beginning of the year, in China, in the final," Li said. "She plays flat, so I think grass is a pretty good surface for her. I need to prepare well for that one on my day off tomorrow."
"I'm feeling pretty good and I'm really pleased with those couple of matches," Stosur said. "And my whole preparation the whole time I've been on the grass, I feel it's been better than ever. I'm just doing everything I can. But the next match is going to be very tough for me. I'll try and do my best."
"She's going to have a much bigger serve than the last two players I've played," Stosur said. "She really plays aggressive and, you know, power, power, power really. So I'll certainly have to try and combat that. I think a big part of the match is going to be serving. We've both got a big serve and are both going to be going for it. And whoever maybe makes as many returns in play as possible too.
"But I think a lot is going to come down to the serve. That's going to be a huge thing."
Elsewhere, No.11 seed Roberta Vinci flirted with defeat but toughed out a marathon 67-minute third set to edge Jana Cepelova, 61 46 97; No.18 seed Dominika Cibulkova routed María-Teresa Torró-Flor, 60 61; Marina Erakovic upset No.24 seed Peng Shuai, 76(6) 62; Tsvetana Pironkova beat Czech qualifier Barbora Zahlavova Strycova, 75 63; and Petra Martic served up a 76(7) 61 win over Karolina Pliskova.
Three women's matches never started due to rain and were postponed until Friday's schedule.