Ana Ivanovic crashes out in Melbourne

Russian teenager Alisa Kleybanova today knocked out fifth seed Ana Ivanovic to reach the fourth round of the Australian Open.

The 19-year-old survived a second-set comeback from former world number one Ivanovic to win 7-5 6-7 (5-7) 6-2.

She appeared to have missed her chance after letting a commanding lead slip away but kept her cool to see off a determined challenge from Ivanovic and set up a fourth-round tie with Jelena Dokic, who beat Caroline Wozniacki earlier.

Last year's beaten finalist Ivanovic relinquished the opening set just as she seemed poised to take it. After forcing the first break in the eighth game her nerve seemed to abandon her just as she was serving for the set.

A double fault let Kleybanova break back and after breaking again the Russian served out for the set.

As the second set started Kleybanova looked to have everything her own way, breaking Ivanovic's serve twice as she raced into a 3-0 lead.

Ivanovic regained her composure to break back before sending a fantastic winner across court to hold her serve for the first time in five attempts. She then tied the set at 3-3 after an unsuccessful appeal from Kleybanova left the 21-year-old with two break points.

But after an exchange of breaks Kleybanova held to put herself back in command, serving for the match. But as had happened to Ivanovic in the first set, the Russian lost her nerve, hitting successive shots beyond the baseline to allow her opponent to break.

Both women held their serve to force an extremely close tiebreak which Ivanovic edged when she smashed a high return from her opponent.

The decisive set began just like the second, with Kleybanova taking a 3-0 lead - with just the one break this time - before Ivanovic began her comeback again.

This time however she only made it as far as 3-2, as despite some tight games the 19-year-old Kleybanova wrapped up the match by breaking her opponent's serve twice more to take the set 6-2.

Meanwhile, top seeds Jelena Jankovic and Dinara Safina have reached the fourth round of the Australian Open after straight sets wins on day five.

It is the first time third seed Safina has gone beyond the third round in Melbourne and she did so with an easy straight sets victory against 25th seed Kaia Kanepi.

"I'm really happy. There's a first time for everything," Safina said after the 6-2 6-2 win.

"Twice I lost in the third round. Today I was like 'that is the third time it should be the luckiest one'.

"I'm glad I won very comfortable today."

The 2008 French Open finalists showed no signs of the rustiness that was evident in her opening two matches against fellow Russians Alla Kudryavtseva and Ekaterina Makarova and sprinted to a 4-0 lead before wrapping up the set in 33 minutes.

The world number three carried that momentum into the second set to take a 4-1 lead and with Kanepi, of Estonia, struggling to contain the Russian's ground strokes the match was wrapped up in little over an hour.

Jankovic took an hour and 41 minutes to beat Ai Sugiyama 6-4 6-4, the third time she has defeated the woman from Japan.

The world number one got the early advantage in the opening set and broke her opponent again in the seventh only to squander her own service game to allow Sugiyama to get back to 5-4.

The 33-year-old Japanese player then appeared to get distracted in the next game when she disputed a late line call and subsequent challenge on Jankovic's serve, and from 30-0 up she lost the game and the set.

Sugiyama, playing in a record 59th consecutive grand slam main draw - and 60th of her career, called for a medical time out towards the end of the match where she had her calves iced and appeared to be suffering some trouble with her breathing.

She was 4-3 down in the second set by then but returned to the court and held her next service game to force the world number one to serve out the match.

"Today was a tough match. I thought I competed much better than in my previous two rounds," Jankovic said.

"Ai is a tough opponent. She doesn't really give me any free points. She fights very well and is a very solid player.

"I had to work for every point I'm just happy to get through this kind of match."

The top seed will face Marion Bartoli in the fourth round after the French 16th seed defeated Lucie Safarova 3-6 6-2 6-1.

Seventh seed Vera Zvonareva had an easy passage into the fourth round with a 6-4 6-1 victory against Italian Sara Errani and will now meet fellow Russian Nadia Petrova who advanced after Galina Voskoboeva, of Kazakhstan, retired hurt after Petrova had won the first set 6-1.