Third seed Kim Clijsters survived her first test of the Australian Open to beat Frenchwoman Alize Cornet 7-6 6-3 and advance to the last 16 on Saturday.
"She was a tricky player," tournament favourite Clijsters told reporters.
"A couple of times out there I didn't finish off my points well."
The Belgian, a three-times grand slam winner and Melbourne runner-up in 2004, struggled to impose herself in the first set on Cornet, celebrating her 21st birthday on a sweltering Rod Laver Arena.
The former world number one's experience showed in the tie-break which Clijsters took 7-3 before normal service resumed in the second set as she found the range with her heavy groundstrokes.
Clijsters squandered two match points on Cornet's serve at 5-2 but moments later it was all over, a deep second serve out wide sealing victory in an hour and 31 minutes.
Cornet, presented with a bouquet of flowers by tournament organisers after the match, insisted she had enjoyed her birthday.
"It was pretty impressive to enter this Rod Laver court against Kim Clijsters," she said with a smile.
"I was feeling a bit stressed the two first games, but I got into the match.
"I have some regrets because I think I could have done better in the first set, and I think I didn't believe enough in myself, so that's just a shame."
Cornet tipped Clijsters to win her first Australian Open crown.
"Yeah, for me she's the favourite," she said.
"She plays very, very fast and close to the line. She's always fights from the first point until the end, and she's very powerful."