2009 US Open – Men's Singles
Juan Martín del Potro defeated five-time defending champion Roger Federer in the final, 3–6, 7–6(7–5), 4–6, 7–6(7–4), 6–2 to win the Men's Singles tennis title at the 2009 US Open. Del Potro became the first Argentine man to win the title since Guillermo Vilas in 1977. This was del Potro's first and so far only major title, although he would reach a second final in 2018. This was also the first final since 1999 to have a five-set final.

Federer was two championship points away from winning the title in the fourth set, as he was attempting to become the first man to win a sixth consecutive US Open title in the Open Era, the first since Bill Tilden in 1925. He was also vying to become the first man to win Grand Slams on clay, grass and hard court in the same calendar year after he won the French Open and Wimbledon earlier that year, and the first player to win the French Open, Wimbledon and US Open in the same calendar year since Rod Laver in 1969. He was on a 41-match winning streak at Flushing Meadows prior to defeat to del Potro. It was the only major not won by the Big Four between the 2005 Australian Open and the 2014 Australian Open, a span of 35 events. This was also where former champion Marat Safin made his final grand slam appearance.

For the first time in US Open history, none of the American players reached the quarterfinals.

Seeds

Qualifying draw

Draw

Finals

Top half

Section 1
{{16TeamBracket-Compact-Tennis5
| RD1=First Round
| RD2=Second Round
| RD3=Third Round
| RD4=Fourth Round
| RD1-seed01=1
| RD1-team01= R Federer
| RD1-score01-1=6
| RD1-score01-2=6
| RD1-score01-3=7
| RD1-score01-4= 
| RD1-score01-5= 
| RD1-seed02=WC
| RD1-team02= D Britton
| RD1-score02-1=1
| RD1-score02-2=3
| RD1-score02-3=5
| RD1-score02-4= 
| RD1-score02-5= 
| RD1-seed03=Q
| RD1-team03= G Lapentti
| RD1-score03-1=3
| RD1-score03-2=6
| RD1-score03-3=6
| RD1-score03-4=0
| RD1-score03-5=69
| RD1-seed04= 
| RD1-team04= S Greul
| RD1-score04-1=6
| RD1-score04-2=4
| RD1-score04-3=3
| RD1-score04-4=6
| RD1-score04-5=711
| RD1-seed05=PR
| RD1-team05= JI Chela
| RD1-score05-1=6
| RD1-score05-2=6
| RD1-score05-3=6
| RD1-score05-4= 
| RD1-score05-5= 
| RD1-seed06= 
| RD1-team06= Ó Hernández
| RD1-score06-1=4
| RD1-score06-2=4
| RD1-score06-3=2
| RD1-score06-4= 
| RD1-score06-5= 
| RD1-seed07= 
| RD1-team07= T Alves
| RD1-score07-1=0
| RD1-score07-2=3
| RD1-score07-3=4
| RD1-score07-4= 
| RD1-score07-5= 
| RD1-seed08=31
| RD1-team08= L Hewitt
| RD1-score08-1=6
| RD1-score08-2=6
| RD1-score08-3=6
| RD1-score08-4= 
| RD1-score08-5= 
| RD1-seed09=21
| RD1-team09= J Blake
| RD1-score09-1=6
| RD1-score09-2=6
| RD1-score09-3=7
| RD1-score09-4= 
| RD1-score09-5= 
| RD1-seed10= 
| RD1-team10=
| RD1-score10-1=1
| RD1-score10-2=4
| RD1-score10-3=5
| RD1-score10-4= 
| RD1-score10-5= 
| RD1-seed11= 
| RD1-team11= O Rochus
| RD1-score11-1=6
| RD1-score11-2=6
| RD1-score11-3=6
| RD1-score11-4= 
| RD1-score11-5= 
| RD1-seed12= 
| RD1-team12= I Kunitsyn
| RD1-score12-1=3
| RD1-score12-2=0
| RD1-score12-3=2
| RD1-score12-4= 
| RD1-score12-5= 
| RD1-seed13=Q
| RD1-team13= P Polansky
| RD1-score13-1=4
| RD1-score13-2=4
| RD1-score13-3=7
| RD1-score13-4=6
| RD1-score13-5=1
| RD1-seed14= 
| RD1-team14={{Nowrap| G García-López}}
| RD1-score14-1=6| RD1-score14-2=6| RD1-score14-3=5
| RD1-score14-4=3
| RD1-score14-5=6| RD1-seed15=Q
| RD1-team15= D Young
| RD1-score15-1=4
| RD1-score15-2=6| RD1-score15-3=2
| RD1-score15-4=3
| RD1-score15-5= 
| RD1-seed16=14
| RD1-team16= T Robredo| RD1-score16-1=6| RD1-score16-2=3
| RD1-score16-3=6| RD1-score16-4=6| RD1-score16-5= 
| RD2-seed01=1
| RD2-team01= R Federer| RD2-score01-1=6| RD2-score01-2=7| RD2-score01-3=7| RD2-score01-4= 
| RD2-score01-5= 
| RD2-seed02= 
| RD2-team02= S Greul
| RD2-score02-1=3
| RD2-score02-2=5
| RD2-score02-3=5
| RD2-score02-4= 
| RD2-score02-5= 
| RD2-seed03=PR
| RD2-team03= JI Chela
| RD2-score03-1=3
| RD2-score03-2=3
| RD2-score03-3=4
| RD2-score03-4= 
| RD2-score03-5= 
| RD2-seed04=31
| RD2-team04= L Hewitt| RD2-score04-1=6| RD2-score04-2=6| RD2-score04-3=6| RD2-score04-4= 
| RD2-score04-5= 
| RD2-seed05=21
| RD2-team05= J Blake| RD2-score05-1=6| RD2-score05-2=3
| RD2-score05-3=78| RD2-score05-4=6| RD2-score05-5= 
| RD2-seed06=  
| RD2-team06= O Rochus
| RD2-score06-1=4
| RD2-score06-2=6| RD2-score06-3=66
| RD2-score06-4=3
| RD2-score06-5= 
| RD2-seed07= 
| RD2-team07=
| RD2-score07-1=2
| RD2-score07-2=6| RD2-score07-3=2
| RD2-score07-4=4
| RD2-score07-5= 
| RD2-seed08=14
| RD2-team08= T Robredo| RD2-score08-1=6| RD2-score08-2=4
| RD2-score08-3=6| RD2-score08-4=6| RD2-score08-5= 
| RD3-seed01=1
| RD3-team01= R Federer| RD3-score01-1=4
| RD3-score01-2=6| RD3-score01-3=7| RD3-score01-4=6| RD3-score01-5= 
| RD3-seed02=31
| RD3-team02= L Hewitt
| RD3-score02-1=6| RD3-score02-2=3
| RD3-score02-3=5
| RD3-score02-4=4
| RD3-score02-5= 
| RD3-seed03=21
| RD3-team03= J Blake
| RD3-score03-1=62
| RD3-score03-2=4
| RD3-score03-3=4
| RD3-score03-4= 
| RD3-score03-5= 
| RD3-seed04=14
| RD3-team04= T Robredo| RD3-score04-1=77| RD3-score04-2=6| RD3-score04-3=6| RD3-score04-4= 
| RD3-score04-5= 
| RD4-seed01=1
| RD4-team01= R Federer| RD4-score01-1=7| RD4-score01-2=6| RD4-score01-3=6| RD4-score01-4= 
| RD4-score01-5= 
| RD4-seed02=14
| RD4-team02= T Robredo
| RD4-score02-1=5
| RD4-score02-2=2
| RD4-score02-3=2
| RD4-score02-4= 
| RD4-score02-5= 
}}

Section 2

| RD1-score09-1=6| RD1-score09-2=6| RD1-score09-3=6| RD1-score09-4= 
| RD1-score09-5= 
| RD1-seed10= 
| RD1-team10= A Seppi
| RD1-score10-1=0
| RD1-score10-2=4
| RD1-score10-3=4
| RD1-score10-4= 
| RD1-score10-5= 
| RD1-seed11=Q
| RD1-team11= S Devvarman| RD1-score11-1=6| RD1-score11-2=6| RD1-score11-3=6| RD1-score11-4= 
| RD1-score11-5= 
| RD1-seed12= 
| RD1-team12= F Gil
| RD1-score12-1=3
| RD1-score12-2=4
| RD1-score12-3=3
| RD1-score12-4= 
| RD1-score12-5= 
| RD1-seed13= 
| RD1-team13= A Golubev
| RD1-score13-1=4
| RD1-score13-2=6| RD1-score13-3=5
| RD1-score13-4=3
| RD1-score13-5= 
| RD1-seed14= 
| RD1-team14= L Mayer| RD1-score14-1=6| RD1-score14-2=4
| RD1-score14-3=7| RD1-score14-4=6| RD1-score14-5= 
| RD1-seed15= 
| RD1-team15= S Bolelli
| RD1-score15-1=4
| RD1-score15-2=4
| RD1-score15-3=4
| RD1-score15-4= 
| RD1-score15-5= 
| RD1-seed16=15
| RD1-team16= R Štěpánek| RD1-score16-1=6| RD1-score16-2=6| RD1-score16-3=6| RD1-score16-4= 
| RD1-score16-5= 
| RD2-seed01=4
| RD2-team01= N Djokovic| RD2-score01-1=6| RD2-score01-2=6| RD2-score01-3=6| RD2-score01-4= 
| RD2-score01-5= 
| RD2-seed02=Q
| RD2-team02= C Ball
| RD2-score02-1=3
| RD2-score02-2=4
| RD2-score02-3=4
| RD2-score02-4= 
| RD2-score02-5= 
| RD2-seed03= 
| RD2-team03= M González
| RD2-score03-1=77| RD2-score03-2=4
| RD2-score03-3=5
| RD2-score03-4=2
| RD2-score03-5= 
| RD2-seed04=Q
| RD2-team04= J Witten| RD2-score04-1=63
| RD2-score04-2=6| RD2-score04-3=7| RD2-score04-4=6| RD2-score04-5= 
| RD2-seed05=23
| RD2-team05=
| RD3-score01-1=6| RD3-score01-2=3
| RD3-score01-3=6| RD3-score01-4=6| RD3-score01-5= 
| RD3-seed02= 
| RD3-team02= D Köllerer
| RD3-score02-1=1
| RD3-score02-2=6| RD3-score02-3=3
| RD3-score02-4=3
| RD3-score02-5= 
| RD3-seed03=24
| RD3-team03= JC Ferrero| RD3-score03-1=1
| RD3-score03-2=6| RD3-score03-3=77| RD3-score03-4=1
| RD3-score03-5= 
| RD3-seed04=9
| RD3-team04= G Simon
| RD3-score04-1=6'''
| RD3-score04-2=4
| RD3-score04-3=65
| RD3-score04-4=0r
| RD3-score04-5=
| RD4-seed01=6
| RD4-team01=

Section 8