MELBOURNE, Australia — It's not difficult to pick the odd one out in this group of 28-year-old players: Roger Federer, Lleyton Hewitt, Nikolay Davydenko.

Federer has won a record 15 Grand Slam titles and is ranked No. 1. Hewitt was No. 1 before Federer hit the scene and has won the U.S. Open and Wimbledon.

They'll meet in the fourth round of the Australian Open after comfortable wins Saturday. Davydenko is on track to play the winner of that match in a quarterfinal.

The balding, 5-foot-10 Russian has never won a major or played in the final of one. He has never been ranked No. 1, reaching a career high No. 3 in 2006. He travels with his wife but doesn't have kids — Federer and Hewitt have two each — although he wouldn't mind one day being a "papa."

He knows that if Federer or Hewitt walked through downtown Melbourne they'd be mobbed for autographs. Davydenko has finished in the top six for the last five years but concedes he'd barely be noticed in Melbourne, or Moscow for that matter.

"Nobody recognize me and it's good feeling really," he said.

He certainly hasn't been sneaking up on players. He is on a 12-match winning streak that includes wins over Federer and Rafael Nadal at last year's season-ending championships in London and the season-opening tournament in Doha. Nor did his pronouncement that the top 10 players were "scared" of him go unnoticed.

"Scared? No," Federer said this week. "Respect him ... Yes."

Davydenko, seed sixth, beat Argentina's Juan Monaco 6-0, 6-3, 6-4 on Saturday and next faces 2009 semifinalist Fernando Verdasco. Verdasco advanced when Stefan Koubek retired because of a virus after losing the opening set 6-1.

Hewitt had to play only 12 games in 54 minutes to advance. Marcos Baghdatis, a 2006 finalist, retired with a right shoulder injury with the Australian leading 6-0, 4-2.

Their last meeting at Melbourne Park was two years ago and significantly more dramatic. Hewitt finally won at 4:34 a.m.

Novak Djokovic, who is ranked No. 3 and beat Federer in the semifinals en route to the 2008 title, defeated Denis Istomin 6-1, 6-1, 6-2 and next plays Poland's Lukasz Kubot. Kubot, who finished last year ranked No. 101, got a walkover when No. 20 Mikhail Youzhny withdrew with a wrist injury.

Jo-Wilfried Tsonga, who lost the 2008 final to Djokovic, got the better of an ailing Tommy Haas to advance 6-4, 3-6, 6-1, 7-5. Next for him is Nicolas Almagro of Spain, who beat Colombia's Alejandro Falla 6-4, 6-3, 6-4.

The Williams sisters moved a step closer to a semifinal meeting, with defending champion Serena beating No. 32 Carla Suarez Navarro 6-0, 6-3 to avenge Venus' loss to the Spaniard in the second round in Australia last year. Serena said she didn't want Suarez Navarro making a habit of "taking out a sister at this time of year."

Serena Williams has won the Australian Open each odd-numbered year since 2003, when she beat Venus in the final. The 11-time Grand Slam singles champion will next face Australia's Samantha Stosur, seeded 13th.

Venus advanced 6-1, 7-6 (4) over Australian wild-card entry Casey Dellacqua and realizes she may have to beat her sister to play for the title.

"Of course I want to progress well to the final, that is my goal," Venus said. "So far, I'm getting closer." Next up is Francesca Schiavone of Italy, who defeated No. 10 Agnieszka Radwanska of Poland 6-2, 6-2.

U.S. Open runner-up Caroline Wozniacki downed Israeli Shahar Peer 6-4, 6-0 to set up a fourth-round against China's Li Na, who advanced 7-5, 3-6, 6-2 over 2008 semifinalist Daniela Hantuchova.

No. 7 Victoria Azarenka of Belarus had a 6-0, 6-2 win over Italy's Tathiana Garbin and will next play No. 9 Vera Zvonareva of Russia, who beat Argentina's Gisela Dulko 6-1, 7-5.

The Andys will open and close play Sunday at Rod Laver Arena. No. 5-seeded Andy Murray plays American John Isner first and No. 7 Andy Roddick faces No. 11 Fernando Gonzalez of Chile in the curtain closer.

In between, Nadal takes on big-serving Croat Ivo Karlovic and former No. 1-ranked Justine Henin, in her Grand Slam comeback after 20 months in retirement, opposes fellow Belgian Yanina Wickmayer.

U.S. Open champion Juan Martin del Potro goes against No. 14 Marin Cilic.

While Davydenko doesn't crave the attention of the bigger stars, he does want a share in the trophies. Only Djokovic and del Potro have interrupted the dominance of Federer and Nadal in the last 19 majors, but Davydenko gives himself a shot.

"I feel I can beat everyone because I've beaten everyone already," he said before the tournament. "I'm feeling like I can win and really play very good tennis."

After 10 straight losses to Federer, Davydenko has won their last two meetings, both in semifinals. Against Nadal, he edged ahead 5-4 after three consecutive wins — all on hard courts in the last 12 months.

"Sometimes I don't understand this feeling. I hope I hold this level," said Davydenko, whose best runs in Australia were quarterfinal exits from 2005-07. "Every day and all this tournament, all these two weeks. Yes, now I want to win. Like say for sure I want to win a Grand Slam right now."

Davydenko made headlines in 2007 when a British bookmaker voided all bets on one of his matches because of suspicious gambling patterns. The Russian withdrew against Martin Vassallo Arguello in the third set of a match in Poland, citing a foot injury. Both players were cleared of any wrongdoing after an ATP investigation.

Davydenko also was fined $2,000 for lack of effort after a loss that same year at the St. Petersburg Open, but the charge was dropped after the Russian won an appeal.

One consequence of Davydenko's ascent has been the increase in questions about himself. He's reveling in the change.

He dealt with the obvious ones quickly: Yes, he does occasionally drink vodka; No, he's not averse to talking about money as, he said, all Russians do.

The more people know about him, the more curious the questions become.

After his win over Monaco, he was asked which Russian tennis player he'd choose to marry — the reporter fishing for Davydenko's take on the most beautiful of the Russians on the women's circuit.

"If I married another tennis player?" he replied, deadpan: "Man or woman?"

Amid the laughter, his eyes widened suddenly as he scanned the room.

"I have already wife," he said, adding quickly. "I have my beautiful wife. I don't want to have any ..."

Then his wife of three years, Irina, chimed into a double-act: "I hear you."

Jokes aside, Davydenko thinks he'll keep improving.

"Really, it's difficult to say why it's happening," he said, shrugging his shoulders. "Because I'm older. It's difficult, really difficult to say why."