Quarterfinal Unknown: Who IS Juan Martin Del Potro?

Rafael Nadal. Andy Roddick. Roger Federer. Novak Djokovic. These four names have become household when it comes to men's tennis.

They are also four of the remaining elite eight in the Australian Open. Among the others are a former tournament runner-up and a trendy, left-handed Spaniard not named Nadal.

And then there is 20-year-old, sixth-ranked Juan Martin Del Potro of Argentina, the youngest quarter-finalist at the Australian Open in 17 years.

But who IS he?

Del Potro is a giant in several ways. Standing 6'6", he is a physically imposing figure on the court. He is also a giant in his home country, leading Argentina's Davis Cup team despite being only 20.

He began the 2008 campaign ranked 50th in the world, only sixth in his own country behind the likes of David Nalbandian and Guillermo Canas. He burst onto the international stage in the summer of 2008, going on a spree leading up to the US Open where he won four consecutive tournaments that bumped him into the top ten.

First, he won on clay at Stuttgart, defeating Frenchman Richard Gasquet 6-4, 7-5.

For his second victory, he charged through a weak field at Kitzbuhel, Austria and demolished local favorite Jurgen Melzer 6-2, 6-1.

Then, he muscled through a veteran field in Los Angeles, and took down Andy Roddick in the final 6-1, 7-6.

Finally, he navigated the field of 128 in Washington, defeating outmatched Viktor Troicki of Serbia 6-3, 6-3.

For those who have never seen Del Potro play, he resembles a Kevin Durant-style power forward with a tennis racket, utilizing his 7'5" wingspan. His footwork is effective as a blinded ostrich at times, but that figures to improve as he grows into his frame. As for now, his long strides can make up for his lack of footwork.

Although his strokes also may be a bit raw at the time; his forehand is mediocre, his backhand is average, and his serve doesn't dance, he will continue to develop as his skills evolve.

In the present, he has exactly the kind of game that can trouble players. He can serve downhill and his shots don't have that kick so many are using today.

He is also an above-average net player. Trying to lob Del Potro at the net is as easy as draining a three-pointer with Yao Ming guarding. The only drawback is that he is reluctant to do it, although he has had some success in that aspect of his game.

Del Potro is a kid playing at a level well beyond his years in 2009 thus far. He's already got a tournament in the bag (Auckland) and is on the verge of his first Grand Slam semifinal.

All that remains in his way is some guy named Roger Federer.