Serena Williams may have to remove sister Venus's number from speed dial after some misguided advice left her scrambling to beat Czech Lucie Safarova at the Hobart International on Tuesday.

"I spoke to Venus before the match, she's played her before and she said that she was a tough opponent," Serena told reporters after squeezing past Safarova 6-3, 3-6, 7-6.

"But Venus didn't give me any good pointers, actually.

"She told me some false information, so I'll be calling her back about that."

The win put Serena into the quarter-finals and went some way towards boosting her confidence following her comeback from a four-month injury break.

Serena, preparing for next week's Australian Open, began well but her game fell apart in the second set and she had to battle all the way to keep her title bid alive.

"It's been a while since I won a tiebreaker and that was in the back of my mind," she said.

"I thought 'I have to win this tiebreaker,' and more than anything that's what I was excited about, even more than winning the match.

"I was really happy to win because I wasn't ready to go home yet," said Serena after booking a quarter-final spot against Austrian Sybille Bammer.

"I wanted to have at least one more match here before the Australian Open, so I was happy to win."

Bammer romped past second seed Anabel Medina Garrigues 6-4, 6-3.