<p>World number one Serena Williams showed plenty of rust in her first competitive outing ahead of the Australian Open, but battled through to defeat Andrea Petkovic at the Brisbane International on Tuesday.<br /><br /></p>.<p>The number one seed won 6-4, 6-4 in 98 minutes to reach the quarterfinals but her 36 unforced errors and 55 percent serving accuracy shows how much Williams has to work on with the first major of 2014 less than a fortnight away.<br /><br />German opponent Petkovic was exactly what the defending champion needed at this point in the season. Ranked 43rd in the world, but a top-ten player before multiple injuries restricted her 2012 campaign, she ensured the five-time Australian Open winner had to fight for every point.<br /><br />"It was an intense match, which was really good for me," Williams told reporters. "She's a good player. She's been in the top ten before and she was on her way to being even better."</p>
<p>World number one Serena Williams showed plenty of rust in her first competitive outing ahead of the Australian Open, but battled through to defeat Andrea Petkovic at the Brisbane International on Tuesday.<br /><br /></p>.<p>The number one seed won 6-4, 6-4 in 98 minutes to reach the quarterfinals but her 36 unforced errors and 55 percent serving accuracy shows how much Williams has to work on with the first major of 2014 less than a fortnight away.<br /><br />German opponent Petkovic was exactly what the defending champion needed at this point in the season. Ranked 43rd in the world, but a top-ten player before multiple injuries restricted her 2012 campaign, she ensured the five-time Australian Open winner had to fight for every point.<br /><br />"It was an intense match, which was really good for me," Williams told reporters. "She's a good player. She's been in the top ten before and she was on her way to being even better."</p>