Serena Williams celebrates after downing Barbora Strycova at Melbourne Park.
Serena Williams celebrates after downing Barbora Strycova at Melbourne Park. Scott Barbour

Class gets struggling Williams through

Uncertain at first, error-prone Serena Williams has charged into her 10th successive grand slam quarter-final, downing Czech Barbora Strycova 7-5 6-4 in the fourth round of the Australian Open.

The world No.2 secured her 47th quarter-final berth from 66 major tournaments - a stunning strike rate - but the nature of her latest success owed more to grit than polish.

The six-time Melbourne Park champion will next face Briton Johanna Konta and no doubt be doubly keen to improve on an unconvincing and nervous display.

The American made 46 unforced errors and, even more unusually, struggled to hold her serve.

"It's good to know that I have a Plan B or another option,” Williams said.

"I wasn't serving my greatest today, but she was putting a lot of returns in there. It's always good to have something improve on ... I can do better with my serve.

"She is a traffic player - what makes it so difficult to play against.

"I think she's a really smart player. She can do everything. She can run, she can come to the net, she can hit slice, she can do that much anything.”

Renowned as one of the world's premier servers, Williams dropped three of her first four service games and lost serve four times for the match.

And her break point conversion against the outclassed Strycova was equally inefficient, taking just six of 14 opportunities.

For the most part, Williams struggled for rhythm.

She needed eight set points to claim the first set after 55 minutes - via a mishit backhand and net cord -and later when serving for the match, she dropped serve again.

Williams eventually progressed in 106 minutes with 28 winners to Strycova's nine.

Chasing a 23rd major overall, Williams said expectation was not a negative factor as she pursued more history.

"I love pressure, I deal well with pressure,” she said. "Obviously I have nothing to lose. Everything is a bonus for me right now.”