Defending Champion Djokovic Through To Quarters

`It`s big relief`, Djokovic said. `I was really happy to get through in the fourth set`.

Serbia's Novak Djokovic kept alive his Australian Open defence with a 6-1 7-6 6-7 6-2 fourth-round win over Marcos Baghdatis of Cyprus that stretched into the early hours of Monday.

Djokovic, steadily growing in confidence with each match of the tournament, survived a spirited comeback from the flamboyant Baghdatis to set up a quarter-final clash with American Andy Roddick, who advanced safely with a 7-5 6-1 6-3 win over Spain's Tommy Robredo.

"It's big relief," Djokovic said. "I was really happy to get through in the fourth set.

"It could really go either way. We had long rallies, even though the results don't show the real picture.

"Once he gets into the rhythm, he's one of the toughest opponents on this surface and I was aware of that."

Djokovic raced through the opening set in 25 minutes but the rest of the match was much tighter as Baghdatis, a finalist at Melbourne Park three years ago, began to find his rhythm after a slow start.

Djokovic fought back from a break down to win the second in a tiebreak but Baghdatis won the third, also in a tiebreak, as the world number three starting to show signs of tiring.

SLOW START

Djokovic regained the initiative when he broke Baghdatis at the start of the fourth then broke him again before serving out for victory after three-and-a-quarter hours on centre court.

"I feel more confident the more wins I have under my belt," Djokovic said.

"It's logical. I did have a slow start in the tournaments before the Australian Open but this was my priority.

"I'm feeling much better on the court mentally and physically and gamewise. Hopefully I can continue in the same way in the quarter-finals."

The match did not end until 2.26 a.m. local time because the start was delayed by the late finish to the previous match between Jelena Dokic and Alisa Kleybanova.

"It's very tough to do but it's part of the job," said Baghdatis, who played a match against Lleyton Hewitt last year that finished at 4.34 a.m., the latest finish in grand slam history.

"I didn't have a lot of confidence because I didn't play for seven months (last year)...so I'm pretty happy with the tournament I played.

"I played four matches, I won three. My objective was to play in the second week of the Aussie Open so I made it by three hours."