MELBOURNE: Novak Djokovic’s third-set wobble against Lleyton Hewitt late Monday spoiled a neat statistic. Had the defending champion won in three sets, the top three men would all have reached the quarterfinals without dropping a set.

Top-seeded Djokovic eventually won 6-1, 6-3, 4-6, 6-3 to join Rafael Nadal and Roger Federer in the last eight.

No.4-ranked Andy Murray lost the first set against first-round opponent Ryan Harrison and hasn’t conceded one since. He beat Mikhail Kukushkin on Friday when the Kazakh retired while trailing 6-1, 6-1, 1-0.

The so-called “big four” have reached the quarterfinals at five straight majors, underlining a gap between them and the rest of the field. Djokovic says it’s an attention to detail that makes the difference.

“Nowadays it’s very physical so you have to work very hard, you have to be dedicated, you have to take care of the smallest details off the court as well, how you organize your life, you have to be emotionally balanced,” he said.

“All these kind of things play a very significant role in your performance on the court.”

Djokovic hasn’t been out of the top 4 since the middle of 2007. He did admit, though, that he’s still getting used to sitting at the top of the tree after a standout 2011 in which he won three of the four majors and overtook Nadal and Federer for the No. 1 ranking.

“I have to accept this life as simple as possible because you can easily get carried away,” the Serbian player said. “There is a lot of temptations, especially when you’re at the top.

“Obviously you get more attention and more temptations to do some things that can affect your performance in a negative way.”

Maria Sharapova is already starting to talk like her career has peaked.

Sharapova won her first major at Wimbledon in 2004, added the U.S. title in 2006 and the Australian in 2008, a year after losing the final at Melbourne Park. She had surgery on her right shoulder later that year and hasn’t added to her Grand Slam collection since.

Asked about how she feels after spending about one-third of her life on tour, she said she felt “fortunate to be sitting in this position and saying that I achieved great success at 17.”

“Obviously maybe if I had achieved it a few years later, I wouldn’t feel like I’ve been on the tour for so long. But I’m certainly not complaining for that because that will probably be the highest note of my career.”

Why?

“Because I never had expected that that would come to my career. I was so naive,” she said. “I mean, I don’t think at that point, when I had won Wimbledon, I understood what it meant. I thought it was just an incredible feeling, and it’s Wimbledon, but I don’t think I actually logically knew what I had done.”

After a few years interrupted by injuries, Sharapova says she’s started to regain her energy and passion after a period of time “kind of at a standstill.” She reached the final at Wimbledon last year, losing to Petra Kvitova, in her best run at a Grand Slam in three years.

“I’m 24 years old, almost 25. I love this sport as much as I loved it, you know, when I was at that age,” she said. “I’ve also been through a lot of tough times. I’ve also said the success that I can achieve, the fact that I got myself back to being top 5 in the world, playing tennis again, playing at a high level, competing at this level is pretty remarkable from where I was on a surgery table, not knowing if I’d ever be able to hit a serve again.

“So just a lot of perspective. If I do achieve a Grand Slam win, something on that level, there’s no doubt that that will be another big moment in my career.”

Ana Ivanovic and Caroline Wozniacki have a sporting interest in common outside of tennis. Both date professional golfers, with Ivanovic involved with Australia’s Adam Scott and Wozniacki in a relationship with Rory McIlroy, the Northern Irishman who won the last U.S. Open.

Ivanovic has been with Scott for a while, spending the last couple of offseasons in Australia, so had some advice when Wozniacki came asking about the traps of dating a golfer.

“She did ask me like what kind of shoes should I take to walk on the course,” Ivanovic said after her fourth-round loss to Petra Kvitova on Monday, when Scott was in the crowd at Rod Laver Arena. The answer, for the record: “Just the most comfortable ones.”