Caroline Wozniacki (born 11 July 1990) is a Danish professional tennis player. She is the current World No. 1 on the WTA Tour. As of 12 September 2011, she has held this position for 48 weeks. She is the first Scandinavian tennis player to hold the top ranking position and 20th overall.
Since her WTA debut in 2005, she has improved her year-end ranking each year until finishing on top in 2010. She has won 18 WTA singles titles as of August 2011, three in 2008, three in 2009, six in 2010 (the most since Justine Henin's ten in 2007),and six in 2011. She was runner-up at the 2009 US Open and the 2010 WTA Tour Championships in Doha to Kim Clijsters. She won the 2006 Wimbledon Girls' Singles title, but has yet to win a Women's Grand Slam title. She also holds two WTA titles in doubles.
The Australian Open was Wozniacki's first major as World No. 1. She lost to Li Na, who had defeated her the previous year, in the semifinals 6–3, 5–7, 3–6, after failing to convert a match point when trying to serve out the match at 5–4 in the second set.
Wozniacki dropped to No. 2 behind Kim Clijsters during the week of 14 February, but regained the top spot the following week. She received a bye to the second round in Dubai where, in the quarterfinals, she beat Shahar Pe'er 6–2, 6–4 to ensure her No. 1 position in the next rankings update. She went on to defeat Svetlana Kuznetsova in the final 6–1, 6–3 to take her 13th career singles title and first of the year.
In Doha she received a bye to the second round and reached the final after defeating Nadia Petrova, Flavia Pennetta and Marion Bartoli in straight sets. She lost to Vera Zvonareva in the final 4–6, 4–6.
In the first Premier Mandatory event of the year, the Indian Wells, Wozniacki made it to the final where she met Marion Bartoli and won 6–1, 2–6, 6–3 for her 14th singles title.
After a first-round bye at the Sony Ericsson Open in Miami, Florida, Wozniacki lost in the fourth round to 21st seed Andrea Petkovic 7–5, 3–6, 6–3. Wozniacki made an uncharacteristic 52 unforced errors and later cited exhaustion as a factor in the loss.
In the Family Circle Cup, Wozniacki made it to the final, where she defeated unseeded Elena Vesnina 6–2, 6–3 to take her third title of the year, fifteenth of her career.
In Stuttgart Wozniacki made it to her fifth final of the year, where she lost to Julia Görges in straight sets.
In Madrid Wozniacki lost to Görges again, this time in the third round. In Rome, she lost to eventual champion Maria Sharapova in the semifinal round, with a 7–5, 6–3 defeat.
At the Brussels Open, Wozniacki reached the semifinals, where she defeated the 3rd seed and reigning French Open champion, Francesca Schiavone 6–4, 4–6, 6–3. In the final – Wozniacki's 6th of the year – she defeated the 8th seed Peng Shuai 2–6, 6–3, 6–3 to win her first red clay title after having won three on the faster green clay.
Wozniacki was the top seed at the French Open, but was defeated in the third round by 28th seed Daniela Hantuchová, 6–1, 6–3.
Wozniacki's next tournament was the e-Boks Sony Ericsson Open in her native Denmark. In the final, she defeated 4th seed Lucie Šafářová 6–1, 6–4 taking her fifth title of the year. At Wimbledon she had straight-set wins until the fourth round but then lost 6–1, 6–7, 5–7 to 24th seed Dominika Cibulková.
At the Rogers Cup, Wozniacki was not able to defend her title and made an early second round exit. She was defeated by Roberta Vinci 6–4, 7–5, despite holding a 5–1 lead in the second set. Wozniacki was the top seed at the 2011 Western & Southern Open in Cincinnati, but lost in the second round to World #76 Christina McHale 4–6, 5–7. Next playing at the 2011 New Haven Open at Yale, Wozniacki won the title for the fourth year in a row, defeating Francesca Schiavone in the semifinals and qualifier Petra Cetkovská in the final, 6–4, 6–1.
At the US Open Wozniacki is the No.1 seed; in the first round the Dane defeated Nuria Llagostera Vives 6–3, 6–1; in the second round Wozniacki defeated Arantxa Rus 6–2, 6–0; and in the third round defeated American Vania King 6–2, 6–4. In the fourth round, Wozniacki fought back from a 7–6, 4–1 deficit, defeating Svetlana Kuznetsova 6–7, 7–5, 6–1. Wozniacki then progressed to the semi-finals by defeating Andrea Petkovic in the quarterfinals 6–1, 7–6. In the semi-finals she lost to Serena Williams 6–2, 6–4.