Talk about a dream finish for the 20 year old Argentinian Juan Martin Del Potro. The US Open Men's Final 2009 match finished up Monday night with the underdog shocking Roger Federer in five sets to stop Federer's streak of US Open titles at five.

Since 2004 Roger Federer has been the only tennis player to win the final Grand Slam tournament of the season. The way he was playing this year entering the championship match it looked like he was rolling to his sixth title. Federer had capped his run in this years' tourney yesterday with a straight sets dismantling of #4 Novak Djokovic which included a ridiculous between the legs shot for a winner. So a pre-game prediction of him rolling through #6 Del Potro for his sixth straight US Open title seemed like the logical pick.

However, if you watched Juan Martin Del Potro's play against #3 Rafael Nadal on Saturday you knew he definitely had the talent to challenge Federer. Del Porto beat Nadal easily in straight sets (6 - 2; 6 - 2; 6 - 2) smacking multiple forehand winners. But the question with Del Potro prior to the championship match was whether the 20 year old had the mental toughness to hang with Federer.

Del Potro answered that question in the fourth set when he was down two sets to one to Federer as they entered the tiebreaker. In the tiebreaker he snapped a couple forehand winners by Federer taking the early 3 - 0 lead. From there he was able to hold his serve and win the tiebreaker 7 - 4, forcing a deciding fifth set.

In the fifth set it looked like the younger player (by almost eight years) was more confident than Federer. Del Potro quickly went ahead as he was able to hold serve to start out the fifth set. From there he started to really get the crowd behind him when he broke Federer in the second game and held serve in the third game to take a three sets to none lead. Del Porto continued his strong play especially on Federer's second serves as he stepped up in front of the baseline to set himself up for some wicked forehand winners. Federer had no answer as he hurt himself by not getting his first serve in and even had some horrible double faults.

So Federer's string of US Open championships is over after five years. There is now another tennis star to challenge Federer and Nadal in the years to come. Juan Martin Del Potro wins his first Grand Slam title at age twenty and the way he played today against possibly the best tennis player ever, it will not be his last.