Henin is less than four weeks into her return from 20 months out of the game but is in sight of an eighth grand slam title after she beat fellow Belgian Yanina Wickmayer 7-6 (7/4), 1-6, 6-3.
Second seed Dinara Safina made a tearful exit after she was forced to withdraw against Maria Kirilenko with a recurrence of the back injury that laid her low over the off-season. Safina was trailing 5-4 and 30-40 on serve when she retired and she said afterwards: "I cannot make any movement. Whatever I try to move, it hurts terribly.
The 23-year-old was diagnosed with an inflamed spine after the end-of-season event in Doha in November and was laid low during the off-season as she attempted to recover for this tournament.
"(It feels) exactly the same like in Doha. Exactly the same. I just cannot move anywhere," she said. "The physio asked me to lie on the table. I said 'I cannot lie'. I cannot make any movement."
Safina now fears a lengthy spell on the sidelines. She added: "I have to go back to Germany to my doctor to speak with him. I did an MRI before I came here and my bone edema was getting much smaller. It could not happen again I hope. It's shocking."
The walkover win for Kirilenko, who turns 23 today, meant she progressed to the last eight of a grand slam for the first time in her career and will play China's Zheng Jie.
Zheng progressed to a grand slam quarter-final for the second time with a 7-6 (7/5), 6-4 win over 31st seed Alona Bondarenko.
Third seed Svetlana Kuznetsova became Nadia Petrova's second big-name scalp in two days after she lost 6-3, 3-6, 6-1 to the 19th seed. Petrova's win came just two days after she thrashed US Open champion Kim Clijsters 6-0, 6-1. Petrova is now the only seed left in the bottom half of the draw and will take on Henin, the former world No 1, who did not have things all her own way as Wickmayer raced through the second set in 29 minutes to level the match before Henin steadied to close out another energy-sapping contest.
"It wasn't easy. She played a great match," Henin said. "Physically it was not easy for me. I missed two years so that's why I love being on the court now.
"It's a great feeling to be back. Everything is going so wel for me just nowl."