On the men's side, one of the sport's top stars will feature a very stiff test in quarterfinal play. On the women's side, two of the more underrated—or at least under-hyped—players in the sport will do battle in a clash that could go either way.

You've got to love the quarterfinals of the Australian Open. It's where the elite separate themselves from the consistently good.

In one match on the top portion of the men's bracket, Novak Djokovic will look to recover from an epic fourth-round clash and defeat the ever-dangerous Tomas Berdych. On the ladies' side, red-hot Agnieszka Radwanska will try to defeat a tough nemesis, Na Li.

Tuesday's action at the Australian Open promises to be fun. Let's preview the top matchups from the men's and women's side.

No. 1 Novak Djokovic vs. No. 5 Tomas Berdych

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On one hand, this isn't the easiest draw for Djokovic, as he comes off an epic, five-set match against Stanislas Wawrinka that lasted five hours. Berdych has largely cruised thus far, winning every set in the first four rounds and only reaching one tiebreaker.

On the other hand, Djokovic is 11-1 all-time against Berdych and has won the last eight meetings between the two. He's also 10-0 against Berdych on hard courts.

Oh, and Djokovic has won the past two Australian Opens and three of the last five. He's pretty darn good at this tournament.

After reading that, the evidence would suggest Djokovic will cruise in this match. But I don't think Berdych goes down without a major fight, and besides, Djokovic is always at his best when you think he's down for the count and he digs deep, winning when his defeat seems inevitable.

I don't think this one will take five hours, but at the very least I think Berdych steals a set, maybe two. But in the end, Djokovic will have too many answers for the many questions Berdych will pose to him.

No. 4 Agnieszka Radwanska vs. No. 6 Na Li  

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Radwanska and Li might not be the biggest name's on the WTA Tour, but this promises to be an excellent match.

Li leads the all-time series 5-4, though Radwanska has won two of the last three matches between the two. But Li holds a 4-1 record in head-to-head matchups on hard courts, so she's got that going for her.

But wait—Radwanska has won has won 13 straight matches and two titles this year, and she hasn't yet dropped a set this tournament. Then again, neither has Li.

Still, I think you have to give Radwanska the advantage here. She had just four unforced errors against Ana Ivanovic in fourth round play, after all, and after being defeated by eventual champion Victoria Azarenka at last year's event in the quarterfinals in three sets, you know she's ready to take the next step.

Sorry, Ms. Li, but this young talent isn't going to be stopped Down Under. Radwanska will win this match, but it should be a heck of a battle.