The 2009 US Open was a tennis tournament played on outdoor hard courts, held from August 31 to September 14, 2009, in the USTA Billie Jean King National Tennis Center at Flushing Meadows, New York City, United States. Originally, it was scheduled to end with the men's singles final match on Sunday, September 13, but due to rain the tournament was extended by one day. Like the Australian Open, the tournament featured night matches.

Former World No. 1 and 2005 US Open women's singles champion, Kim Clijsters, competed in the 2009 US Open after being granted a wild card entry, returning to professional tennis after more than two years of retirement. She made it to the women's singles semi-finals, where she knocked out the defending champion Serena Williams in controversial circumstances. In the final, Clijsters defeated Caroline Wozniacki, the first Dane, man or woman, to reach a Grand Slam final in the Open Era, in straight sets: 7–5, 6–3. Clijsters thus became the first mother to win a Grand Slam since Evonne Goolagong Cawley in 1980. In the process, she also became the first unseeded player and wildcard to win the tournament.

In the men's singles final, five-time defending champion Roger Federer lost to Argentina's Juan Martín del Potro in a match lasting over four hours.

Arthur Ashe Kids' Day The Arthur Ashe Kids' Day was held on August 29, 2009, prior to the start of the tournament. It featured an exhibition tennis match involving American player Andy Roddick and Great Britain's Andy Murray, who were joined by actor and comedian Will Ferrell. American Idol winner Jordin Sparks performed her hit single "Battlefield", along with rising stars Honor Society and Justin Bieber. There were also tennis matches and contests featuring Serena Williams, Ana Ivanovic Andy Roddick, Roger Federer, Maria Sharapova, Kim Clijsters, and James Blake. The popular tennis and music festival, which included interactive games, musical entertainment and tennis clinics, was hosted by television personalities Susie Castillo and Quddus.

Singles players

Men's singles ChampionRunner-up Juan Martín del Potro Roger Federer Semifinals out Novak Djokovic Rafael Nadal Quarterfinals out Robin Söderling Fernando Verdasco Fernando González Marin Čilić 4th round out Tommy Robredo Nikolay Davydenko Radek Štěpánek John Isner Jo-Wilfried Tsonga Gaël Monfils Juan Carlos Ferrero Andy Murray 3rd round out Lleyton Hewitt James Blake Sam Querrey Marco Chiudinelli (Q) Jesse Witten (Q) Philipp Kohlschreiber Tommy Haas Andy Roddick Julien Benneteau Tomáš Berdych José Acasuso Nicolás Almagro Daniel Köllerer Gilles Simon Denis Istomin Taylor Dent (WC)2nd round out Simon Greul Juan Ignacio Chela (PR) Olivier Rochus Guillermo García López Marcel Granollers Kevin Kim Mikhail Youzhny Jan Hernych Carsten Ball (Q) Máximo González Somdev Devvarman (Q) Leonardo Mayer Florent Serra Robert Kendrick Marsel İlhan (Q) Marc Gicquel Jarkko Nieminen Viktor Troicki Horacio Zeballos (Q) Josselin Ouanna (Q) Andreas Beck David Ferrer Robby Ginepri Nicolas Kiefer Jürgen Melzer Pablo Cuevas Philipp Petzschner Thomaz Bellucci (Q) Jesse Levine (WC) Nicolás Lapentti Iván Navarro Paul Capdeville1st round out Devin Britton (WC) Giovanni Lapentti (Q) Óscar Hernández Thiago Alves Rubén Ramírez Hidalgo Igor Kunitsyn Peter Polansky (Q) Donald Young (Q) Albert Montañés Mischa Zverev Dudi Sela Michael Yani (Q) Paul-Henri Mathieu Potito Starace Rainer Schüttler Dieter Kindlmann (Q) Ivan Ljubičić Juan Pablo Brzezicki (Q) Karol Beck Igor Andreev Andreas Seppi Fred Gil Andrey Golubev Simone Bolelli Benjamin Becker Janko Tipsarević Martín Vassallo Argüello Alejandro Falla (Q) Victor Hănescu Christophe Rochus Dmitry Tursunov Björn Phau Chase Buchanan (WC) Fabio Fognini Flavio Cipolla Peter Luczak (LL) Wayne Odesnik Michael Berrer (Q) Rajeev Ram Nicolás Massú Jérémy Chardy Evgeny Korolev Marcos Daniel Alberto Martín Steve Darcis Andrei Pavel (PR) Michaël Llodra (WC) Richard Gasquet Juan Mónaco Marat Safin Chris Guccione (WC) Rui Machado (LL) Fabrice Santoro Sergiy Stakhovsky Lu Yen-hsun Daniel Gimeno Traver Ryan Sweeting (WC) Teymuraz Gabashvili Brendan Evans (WC) Stan Wawrinka Ivo Karlović Feliciano López Victor Crivoi Ernests Gulbis

Women's singles ChampionRunner-up Kim Clijsters (WC) Caroline Wozniacki Semifinals out Yanina Wickmayer Serena Williams Quarterfinals out Kateryna Bondarenko Melanie Oudin Li Na Flavia Pennetta 4th round out Petra Kvitová Gisela Dulko Nadia Petrova Svetlana Kuznetsova Francesca Schiavone Venus Williams Vera Zvonareva Daniela Hantuchová 3rd round out Dinara Safina Sara Errani Anastasia Rodionova (Q) Yaroslava Shvedova Maria Sharapova Zheng Jie Sorana Cîrstea Shahar Pe'er Victoria Azarenka Maria Kirilenko Kirsten Flipkens Magdaléna Rybáriková Elena Vesnina Aleksandra Wozniak Vania King (WC) María José Martínez Sánchez2nd round out Kristina Barrois Tathiana Garbin Patty Schnyder Peng Shuai Shenay Perry (Q) Sabine Lisicki Alona Bondarenko Jelena Janković Elena Dementieva Carla Suárez Navarro Alizé Cornet Julie Coin Petra Martić (Q) Stéphanie Dubois Christina McHale (WC) Anastasija Sevastova Barbora Záhlavová-Strýcová (Q) Stefanie Vögele Michelle Larcher de Brito Agnieszka Radwańska Marion Bartoli Anabel Medina Garrigues Chang Kai-chen (Q) Bethanie Mattek-Sands Anna Chakvetadze Jill Craybas Amélie Mauresmo Sania Mirza Samantha Stosur Timea Bacsinszky Angelique Kerber (Q) Melinda Czink1st round out Olivia Rogowska (WC) Urszula Radwańska Mallory Cecil (WC) Alisa Kleybanova Lucie Šafářová Arantxa Rus Jarmila Groth Virginie Razzano Ana Ivanovic Monica Niculescu Lourdes Domínguez Lino Aravane Rezaï Alla Kudryavtseva Ekaterina Makarova Maša Zec Peškirič Roberta Vinci Camille Pin (Q) Anastasia Pavlyuchenkova Polona Hercog Tsvetana Pironkova Anna-Lena Grönefeld Monique Adamczak (Q) Eva Hrdinová (Q) Katarina Srebotnik Galina Voskoboeva Séverine Brémond Beltrame Kristina Mladenovic (WC) Ayumi Morita Ágnes Szávay Varvara Lepchenko Tamarine Tanasugarn Julia Görges Alexandra Dulgheru Marta Domachowska (Q) Alberta Brianti Yvonne Meusburger (Q) Raluca Olaru Mathilde Johansson Mariya Koryttseva (Q) Patricia Mayr Rossana de los Ríos Viktoriya Kutuzova Jelena Dokić Gail Brodsky (WC) Kaia Kanepi Valérie Tétreault (Q) Iveta Benešová Vera Dushevina Nuria Llagostera Vives Yurika Sema (Q) Carly Gullickson (Q) Lucie Hradecká Tatjana Malek Laura Granville (PR) Olga Govortsova Edina Gallovits Ai Sugiyama Anastasiya Yakimova Vesna Manasieva (Q) Meghann Shaughnessy (PR) Sybille Bammer Andrea Petkovic Maria Elena Camerin Alexa Glatch (WC)

Player of the day Day 1: Kim Clijsters, for winning her first match at the US Open in 4 years. Day 2: Jesse Witten, for defeating 29th-seeded Igor Andreev 6–4, 6–0, 6–2 his first career win at a Grand Slam at the age of 26 and ranked 276. Day 3: Flavia Pennetta, for defeating Sania Mirza 6–0, 6–0, which was her third consecutive 6–0 set. Day 4: Melanie Oudin, ranked 70th, for eliminating world #4 Elena Dementieva, after losing the first set and overcoming a thigh injury to win the final set. Day 5: Francesca Schiavone, for defeating #8 seed Victoria Azarenka despite losing the first set. Day 6: Melanie Oudin, for defeating former world #1 and the 29th seed Maria Sharapova, losing the first set and winning 7–5 in the third. Day 7: Jo-Wilfried Tsonga, For reaching the round of 16 for the first time, and for not dropping a set to this point. Day 8: Kateryna Bondarenko, for beating Gisela Dulko in only 47 minutes 6–0, 6–0, advancing to her first grand slam quarterfinal. Day 9: Marin Čilić, for defeating ATP No. 2 Andy Murray in three sets. Day 10: Yanina Wickmayer, for defeating Kateryna Bondarenko in straight sets and becoming the second Belgian player in the semifinals. Day 11: Juan Martín del Potro, for defeating Marin Čilić in four sets to advance to the semifinals of the US Open for the first time. Day 12: No matches played due to rain. Day 13: Caroline Wozniacki, for beating Yanina Wickmayer 6–3, 6–3 in the semifinals, thus becoming the first Dane, man or woman, to reach a Grand Slam final in the Open Era. Day 14: Roger Federer, for beating Novak Djokovic in the semifinals 7–6(7–3), 7–5, 7–5, thus reaching his 21st Grand Slam and 6th consecutive US Open final. Day 15: Juan Martín del Potro, for winning his first Grand Slam title, ending Roger Federer's streak of consecutive US Open championships at five.

Day-by-day summaries

Day 1 (August 31)

The first day of the tournaments saw many seeds get through pretty easily in straight sets: Roger Federer, James Blake, Lleyton Hewitt, Nikolay Davydenko and Radek Štěpánek. The day also produced a couple of upsets, when Mikhail Youzhny continued 26th seeded Paul-Henri Mathieu's horrible US Open record by beating him in four. While, tall American John Isner did the same to 28th seeded Victor Hănescu by ending the Romanian's 2009 bid in three with the second set going to a tie-break 16–14. The exciting day continued with a couple of five-set marathons, with Simon Greul defeating Giovanni Lapentti, Guillermo García López out-lasting Peter Polansky, and Jan Hernych surviving against Rainer Schüttler. The days last match featured America's hope Andy Roddick prevailing over Björn Phau in straight sets in a match that started at 11:00 pm.

On the women's side, former world no. 1 Kim Clijsters opened the play, winning over Viktoriya Kutuzova losing only two games. Joining her were defending 2009 Wimbledon and Australian Open champion Serena Williams, Amélie Mauresmo, Victoria Azarenka, Flavia Pennetta, Elena Vesnina, Agnieszka Radwańska, Li Na and Marion Bartoli who all won in two sets. Australian Samantha Stosur was pushed by veteran player Ai Sugiyama in three sets, Daniela Hantuchová got past American Meghann Shaughnessy in three as well. In the first night match, Venus Williams was able to claw her way to avoid an upset to win against Russian Vera Dushevina in a very close three-setter. Venus committed four foot faults in the match. With Venus and Serena getting past the first round, a few American players saw success on the women's side with Vania King, Bethanie Mattek-Sands, and Jill Craybas getting to the second round. Austrian and 28th seeded Sybille Bammer, who defeated Serena Williams in Cincinnati, and 25th seeded Kaia Kanepi were the only casualties of the day.

Seeds out: Men's singles: Paul-Henri Mathieu , Victor Hănescu Women's singles: Kaia Kanepi , Sybille Bammer Schedule of play

Matches on Arthur Ashe Stadium Event Winner Loser Score Women's singles – 1st round Kim Clijsters [WC] Viktoriya Kutuzova 6–1, 6–1 Men's singles – 1st round Roger Federer Devin Britton [WC] 6–1, 6–3, 7–5 Women's singles – 1st round Serena Williams Alexa Glatch [WC] 6–4, 6–12009 US Open Opening Night Ceremony Women's singles – 1st round Venus Williams Vera Dushevina 6–7(5–7), 7–5, 6–3 Men's singles – 1st round Andy Roddick Björn Phau 6–1, 6–4, 6–2Matches on Louis Armstrong Stadium Event Winner Loser Score Women's singles – 1st round Victoria Azarenka Alexandra Dulgheru 6–1, 6–1 Men's singles – 1st round John Isner Victor Hănescu 6–1, 7–6(16–14), 7–6(7–5) Women's singles – 1st round Amélie Mauresmo Tatjana Malek 6–3, 6–4 Men's singles – 1st round James Blake Rubén Ramírez Hidalgo 6–1, 6–4, 7–5 Women's singles – 1st round Daniela Hantuchová Meghann Shaughnessy [PR] 6–2, 4–6, 6–1Matches on the Grandstand Event Winner Loser Score Men's singles – 1st round Mikhail Youzhny Paul-Henri Mathieu 2–6, 7–5, 6–0, 6–2 Women's singles – 1st round Flavia Pennetta Edina Gallovits 6–0, 6–4 Women's singles – 1st round Vera Zvonareva Nuria Llagostera Vives 6–0, 6–4 Men's singles – 1st round Lleyton Hewitt Thiago Alves 6–0, 6–3, 6–4Colored background indicates a night match

Day 2 (September 1)