Melbourne, Jan 25 (DPA) Novak Djokovic took a step closer to a possible second title at the Australian Open with a dominating 6-1, 6-2, 7-5 defeat of Pole Lukasz Kubotonday as the Grand Slam began its second week.
The third-seeded Serb has a theoretical chance to gun for world number one.

Djokovic could take over the top spot should Roger Federer fail to reach the semi-finals and Djokovic duplicate his 2008 title at Melbourne Park.

World number two Rafael Nadal is also within sight of the Serb should the Spanish defending champion falter in the closing stages.

Federer and longtime rival Lleyton Hewitt will be lighting up the night session in a fourth-round classic, with Aussie Hewitt trying to beat the Swiss master for the first time in seven years after losing their last 14 encounters.

Djokovic wasted little energy with 11 aces, 37 winners and six breaks of serve over his 86th-ranked opponent, who advanced in a walkover in the third round at the weekend.

Djokovic’s victory was his 70th at a Grand Slam and 18th in Melbourne against four defeats.

In the women’s fourth round, China’s Li Na swamped Danish fourth seed Caroline Wozniacki 6-4, 6-3 to reach the third Grand Slam quarter-final of her career.

“I had my chances, especially in the first set leading all the time,” Wozniacki said. “I had my chance for 5-2, I didn’t take it.

“I tried to hang in there. But it didn’t go my way today.”

Li holds a 1-0 record over upcoming sixth-seeded opponent Venus Williams, the US player booking her spot with a comeback over Italy’s Francesca Schiavone 3-6, 6-2, 6-1.

Li beat Williams in the Beijing quarter-finals two years ago. The Chinese player reached the quarters at last year’s US Open and Wimbledon in 2006.

The winner came through on her second match point, firing 21 winners and breaking seven times.

Williams overcame a poor start against Schiavone, turning the tables to survive as the major began its concluding second week.

“She played really well in the first set, I have to give her credit,” said Williams, a five-time Wimbledon winner. “She just played really aggressively, doing everything she needed to do to win the match.

“But obviously it takes a lot to close out a match, especially on an important match like that one. I was able just to get some footing back in and start to execute the way I wanted to.

“I’m ready to go and I feel very well. Obviously I’m hitting the ball pretty good, especially against her today. She was really playing well,” Williams said.