Top seed Justine Henin had to work harder than expected to beat Olga Poutchkova 6-1 7-5 in the second round of the Australian Open in Melbourne.
Henin struggled to close out her match against Poutchkova
The world number one's game deserted her in the second set and she let a 5-2 lead slip away before recovering.
Defending champion Serena Williams and third seed Jelena Jankovic join her in round three after emphatic victories.
And France's Amelie Mauresmo is also through, despite needing 10 match points to see off Yaroslava Shvedova.
Mauresmo, the 2006 champion, looked nervous in the closing stages but eventually won through 6-4 7-6 (7-5).
"The tension got to me," the 18th seed admitted. "I probably got a little bit tight and really wasn't able to finish the match off."
Alicia is the hometown hero here and had all the support but I think I played really well
Williams made short work of China's Yuang Meng, clinching a 6-3 6-1 win in 71 minutes despite being well short of her best form.
Jankovic also wobbled at times during her match with Romania's Edina Gallovits, but her biggest concern was a niggling shoulder injury and she came through 6-2 7-5 and will play 30th seed Virgine Razzano next.
Meanwhile, 12th seed Nicole Vaidisova was an impressive winner over Melbourne resident and Australian hope Alicia Molik, triumphing 6-2 6-3.
"I am definitely happy with my performance," Vaidisova said. "Alicia is the hometown hero here and had all the support but I think I played really well."
But Australia do have a representative in the third round after Casey Dellacqua knocked out 15th seed Patty Schnyder 4-6 7-5 8-6.
The 22-year-old will face Mauresmo after reaching the third round of a Grand Slam tournament for the first time in nine attempts.
Henin, meanwhile, was left to reflect on her loss of form.
The 25-year-old said: "I lost some intensity on my serve and it was tough at the end."
"When she came back at five-all I understood it was time to push myself a little bit more."
Williams will play 26th seed Victoria Azareka of Belarus in the third round
It was a 30th straight win for the Belgian, who has lost only one match since May 2007, but she was not at her best at the Rod Laver Arena.
Henin looked like she was on course for a routine victory in the early stages but Poutchkova, ranked 97th, began to find her range with a powerful backhand and Henin's serve disintegrated.
Five games in a row went against serve in the second set as both players struggled and, although Henin eventually steadied herself to move into a 5-2 lead, Poutchkova was still causing her problems.
Poutchkova saved three match points to come back from 5-2 down to level the second set before Henin recovered her poise to break again and seal victory to set up a third round clash with Italy's Francesca Schiavone.
Schiavone, the 25th seed, beat Angelique Kerber in straight sets.
But France's Aravane Rezai caused an upset when she beat compatriot and 13th seed Tatiana Golovin 6-3 3-6 6-3.