Defending champ Juan Martin del Potro avenged his Wimbledon loss to Lleyton Hewitt today in Washington by defeating the former No. 1 player in the world 6-4, 3-6, 7-6 (7-2).

The two hour and 22 minute slugfest featured high drama by the two great champions. Hewitt was forced to save two match points in set three, which was aided by winning 82 percent of his first serve points and striking 13 aces.

Del Potro, by contrast, pounded 18 aces and won 75 percent of his first serve points. Both competitors were able to break serve on three occasions in the 195 point contest.

The No. 2 seeded Argentine served for the match at 5-4 in the third set, only to have his grasp of victory stolen by the feisty Aussie. Although Hewitt’s return of serve prowess is widely known for being the best in the game, it was the much improved and impressive serving stats of the Argentine which inevitably led him to victory.

Del Potro’s serve has become a distant echo of what it use to be. He has added power and variety to his once meek delivery, surrounding his game with minimal weaknesses. At this point, if the Argentine can improve on his movement—a tough task considering he’s 6′6″—and become more competent at net, only two players in the world will have a realistic shot at defeating him.

With the win, the sleeveless 2008 champ will move onto the quarterfinals, where he will meet No. 5 seed Robin Soderling, who defeated Marc Gicquel 7-5, 5-7, 6-3. La Sod advanced to the quarterfinals on the strength of 82 percent of his first serve points won, 15 aces, and three breaks of serve.

Rocking Robin will be looking to continue his hot streak from Paris, which has seen the current world No. 12 reach the fourth round of Wimbledon and triumph on the clay of Bstaad. The victory on home soil became the first ever clay-court crown for Soderling.

Del Potro and Soderling have met twice on the ATP World Tour, with each man winning on one occasion. Del Potro defeated Soderling in Auckland earlier this season en route to his fifth career title.

At this point, a quarterfinal affair between these two heavy hitting, in-form players would have to be considered a coin flip.

Elsewhere, No. 1 seed Andy Roddick proved once again that there is no doubt that he is America’s top player. The three-time champ poured in an intelligent performance by diffusing the mighty efforts of countryman Sam Querrey, 7-6 (7-4), 6-4.

Querrey was coming into tonight's contest on the heals of three straight tour finals, as well as his first title of 2009 in Los Angeles over the weekend.

The win for Roddick was also the 500th of his career.

Roddick was efficient but not powerful in his efforts this evening. He allowed Querrey to play the power card in the hopes that his one-speed opponent would falter.

Going forward in the career of Querrey, it will be imperative that the big man adds different dimensions of variety to his game. Up until this point, Querrey has been able to defeat lower ranked opponents based on sheer pace. However, when going up against a player of Roddick’s caliber, a different mind-set needs to be considered.

Querrey will learn the hard way, and he should look to James Blake as an example of how not to design a game style.

With the win, Roddick will advance to the quarterfinals, where he will meet No. 11 seed Ivo Karlovic, who dismissed Somdev Devvarman 7-5, 6-1. Karlovic blasted his way past his overmatched opponent, striking 14 aces and winning 90 percent of his first serve points.

Roddick and Karlovic have met five times on the ATP World Tour, with the American holding a 4-1 head-to-head lead. Aces and tie breakers will undoubtedly be flying all over center court come Friday evening.

No. 4 seed Fernando Gonzalez kept his quest alive for a second Washington final (2003), by defeating American Wayne Odesnik 6-2, 6-4. The win for Gonzo sets up a mouth-watering quarterfinal clash with No. 10 seed Tommy Haas. The German progressed to his fourth straight quarterfinal after dispatching Spaniard Juan Carlos Ferrero 7-5, 2-6, 6-1.

Haas and Gonzalez have met three times on the ATP World Tour, with Gonzalez holding a slight 2-1 head-to-head lead. The pair has not faced each other since 2007.

No. 8 seed Tomas Berdych was also a winner on Thursday, battling past German Philipp Petzchner 4-6, 6-3, 6-3.

Berdych will await either John Isner or French qualifier Sebastian De Chaunac.

Please check back, as I will have a full quarterfinal recap from Washington, DC—The Legg Mason Tennis Classic. Cheers.