Roger Federer eyed his third Grand Slam title in a row, while Juan Martin del Potro was playing in his first major final.
Roger Federer entered the 2009 US Open looking unbeatable—not only in New York, but everywhere. The Swiss captured his first French Open title earlier in the summer, then followed that up with his sixth Wimbledon title. He was going for his sixth US Open title in a row and trying to become the first man to win major titles on clay, grass and hard courts in one year. On his way to the final, he only dropped two sets.
On the bottom half of the draw, the third seed Rafael Nadal was making his return to Grand Slam play after being forced to skip Wimbledon due to injury. He advanced to the semifinals where he met an unexpected opponent, 20-year-old Argentinian Juan Martin del Potro, the number-six seed. Del Potro bludgeoned him off the court, just like he did a few weeks prior in the quarterfinals in Toronto, to reach his first major final and set up his second Grand Slam encounter against Federer in 2009, after their five-set classic in Paris, which Federer won.
Federer came out firing early on just one of the courts he had made his own over the years, and took the opener 6-3. He notched a break early in the second set for a 2-0 lead, and it started to look like the rout was on.
Federer served for a two sets to love lead at 5-4, 30-0. Del Potro rallied to 30-30, then earned a break point after a challenge on an out call. The call frustrated Federer as he lost the next point and his advantage as the score was knotted at 5-5. They held until the tiebreak, which del Potro won to even the match at a set apiece.
In the third set, the intensity went up—and then some. As they changed sides at 5-4, the normally stoic Federer got into a lengthy argument with the chair umpire over the amount of time del Potro was taking to make challenges. Federer went on to take the set 6-4, and with it a two sets to one lead.
The fourth came down to another tiebreak with Federer only seven points away from a sixth consecutive US Open title. It was del Potro, though, who won the set to level the match. Del Potro posted an early break in the fifth set, consolidated it and then broke again at the end to win his first Grand Slam title.
That was the last time a player won the men's title at the US Open without having captured a Masters 1000 title in their career like del Potro did in '09. In 2001, it was Lleyton Hewitt, and before that, it was Hewitt's countryman Patrick Rafter in 1997.
2009 marked the third time in four years that Federer reached all four Grand Slam finals in a single season.
After winning the first two finals of his career in consecutive weeks on clay in 2008, del Potro's next seven final-round appearances came on hard courts.