Del Potro's Open win a new chapter for tennis

Twenty-year-old Argentinean Juan Martin del Potro, aka "The Tower of Tandil," won his first major title on Monday at the U.S. Open, where he defeated Roger Federer in five sets. Here are five reasons why his victory changes the tennis landscape more than any win since Rafael Nadal's first French Open title in 2005.

1. He wasn't in awe of Federer. Most of Federer's opponents can't handle the pressure of playing a tennis legend. Pretty much every player on the ATP Tour considers Federer the greatest player of all time, and he's a nice guy, too. Everyone likes him and looks up to him. Not many players, unfortunately, seem to think they are worthy of beating him (Nadal being the exception). Del Potro looked feeble against Federer at the Australian Open earlier this year, when he lost two love sets to him in the quarterfinals, and he started out in similar fashion in the U.S. Open final. By the middle of the match, though, del Potro was playing with confidence and aggressiveness. Few men have been able to do this against Federer, never mind at the U.S. Open, which Federer had won five years in a row.

2. He came from behind. The last man to defeat Federer in a major tournament after trailing two sets to one was Marat Safin in the 2005 Australian Open semifinals. Only two other men have done this against Federer, according to ATPWorldTour.com: Tommy Haas at the 2002 Australian Open and Jiri Novak at Wimbledon in 1999, when the 17-year-old Federer was ranked outside the Top 100. To do it on a stage this large shows how tough del Potro can be.

3. He won without his A-game. The U.S. Open final is the toughest major final in the sport. It's held the day after the semifinals, so the players are a bit more tired than usual. It begins in late-afternoon shadows, and often ends under the lights. This year, the wind was strong. Del Potro hadn't played at night the entire tournament and he plays a riskier game than Federer, which is more dangerous in difficult conditions. He missed far more easy shots in this match than he did against Nadal in the semifinals or, for that matter, in any other round of the tournament. Yet he kept his composure and made adjustments to his tactics when necessary. That's the sign of a champion.

4. He showed off a new weapon. Great players introduce something new to the sport. John McEnroe reinvented touch. Pete Sampras redefined the serve. Ivan Lendl brought fitness to a new level. Federer has super-charged the all-court game of yesteryear; Nadal makes the topspin of the 1980s look like slice. Del Potro's contribution is the hardest forehand in the history of the game (one was clocked at 110 mph). I've never seen a player who could consistently hit winners from four feet behind the baseline and wide of the doubles alley. If del Potro can continue to hit that shot, and even improve it, he'll be a threat to win every tournament he plays.

5. He can get a lot better. Del Potro is 20 years old and hardly in extraordinary condition. He can add muscle to his lanky frame and improve his stamina. He can refine his volley technique and his slice backhand. If he has the desire to do these things, he's going to be a great player for years to come.