Former world number one Venus Williams stumbled into the third round of the Australian Open with an unimpressive 7-5 6-4 win over France's Camille Pin.
Williams made a raft of unforced errors against Pin
The eighth seed was grateful to edge a tight first set and her erratic serve did not improve in the second either.
Pin battled on but Williams' superior power eventually brought her victory.
Second seed Svetlana Kuznetsova was also tested, trailing 2-5 in the first set to Bulgaria's Tsvetana Pironkova before triumphing 7-6 (7-0) 6-2.
But fourth seed Ana Ivanovic was in sensational form as she crushed Tathiana Garbin 6-0 6-3 in the opening match of Wednesday's night session.
Cheered on by her Australian-based relatives and the local expatriate Serb community, she took the opening set 6-0 in 24 minutes.
"I just played an awesome match, I really hope I can keep at this level and play as long as possible here," said Ivanovic.
Williams, who made 44 unforced errors, admitted she found it tough going against the world number 90 in her victory.
"I feel like I know how to play. If I make a few mistakes, I'm not going to freak out. I'm fine, I feel good
Pin's tenacious style saw her run down every shot she could reach and Williams became frustrated at being unable to finish off points which should have been hers.
"She's really a fighter, so I had to hang in there," Williams, 27, said. "But I finally got a little smarter in the last few games.
"At first, I think I wanted to rush a little bit too much. But finally, later in the second set, I finally realised, 'Whoa, she wants to run, well let her run', so it became a side-to-side kind of thing."
And the six-times Grand Slam winner, who plays India's Sania Mirza in round three, is certain she can improve.
"Nothing worries me anymore," Williams said. "I feel like I know how to play tennis. If I make a few mistakes, I'm not going to freak out. I'm fine, I feel good."
"Whether or not I have had my best match or a match that's not so good for me is not something that worries me for the next round,"
"Either way, it's just important for me to get to the next round. I feel like I can always play better, even if I play well."
Kuznetsova will also know she has to up her game after a hard-fought victory over Pironkova.
"It was really hard," the 2007 US Open runner-up said. "Tsvetana played really well and I just tried to stay in the match and play my best - in the end I came out a winner."
The 22-year-old made a sluggish start and a misfiring second serve combined with several unforced errors saw her quickly fall 0-3 behind.
I just tried to put more balls in play and tried to make rallies long. She's not very consistent, so I wanted to play with her
Only when the Russian was on the brink of losing the first set did she find her form, winning four games in a row before completely dominating the ensuing tie-break.
That disheartened Pironkova and, although she broke Kuznetsova again at the start of the second set, she faded badly and was beaten in 91 minutes.
Kuznetsova, who will play Poland's Agnieszka Radwanska in the third round, added: "I just tried to put more balls in play and tried to make rallies long. She's not very consistent, so I wanted to play with her."
Elsewhere, sixth seed Anna Chakvetadze set up an enticing third round meeting with fellow Russian Maria Kirilenko by beating Alisa Kleybanova 6-3 6-4.
Kirilenko, the 27th seed, thrashed Japanese veteran Akkiko Morigami 6-1 6-1.
And ninth seed Daniela Hantuchova saw off France's Alize Cornet 6-2 7-5 to continue her progress.