The Betty Barclay Cup was a WTA Tour tennis event that was held from 1982 to 1983 (in Hittfeld) and again from 1987 through to 2002. It existed under several different names but was most commonly known as the Citizen Cup (1987–1995) or the Betty Barclay Cup (1999–2002). It was held in Hamburg, Germany and was played on outdoor clay courts.

It existed as a lower tier tournament in the first five years of its run but in 1990 was promoted to Tier II status which it maintained for the rest of its run. Steffi Graf holds the record for the most wins at the event, winning it six times consecutively from 1987–1992. She also finished runner-up a further two times.

The event is also infamous for being the location where Monica Seles, the world number one at the time, was stabbed on April 30, 1993 by a German tennis fan during a quarterfinal match with Magdalena Maleeva. Seles never played in Germany again after the incident.

Hamburg ( /ˈhæmbɜrɡ/; German pronunciation: [ˈhambʊɐ̯k], local pronunciation [ˈhambʊɪç]; Low German/Low Saxon: Hamborg [ˈhaˑmbɔːx]), officially Free and Hanseatic City of Hamburg, is the second-largest city in Germany, the thirteenth largest German state, and the sixth-largest city in the European Union. The city is home to over 1.8 million people, while the Hamburg Metropolitan Region (including parts of the neighbouring Federal States of Lower Saxony and Schleswig-Holstein) has more than 4.3 million inhabitants. Situated on the river Elbe, the port of Hamburg is the second largest port in Europe (after the Port of Rotterdam) and 11th-largest worldwide.

Hamburg's official name, Free and Hanseatic City of Hamburg (German: Freie und Hansestadt Hamburg), reflects Hamburg's history as a member of the medieval Hanseatic League, as a free imperial city of the Holy Roman Empire, and that Hamburg is a city-state and one of the sixteen States of Germany.

Hamburg is a major transport hub in Northern Germany and is one of the most affluent cities in Europe.  It has become a media and industrial centre, with plants and facilities belonging to Airbus, Blohm + Voss and Aurubis. The radio and television broadcaster Norddeutscher Rundfunk and publishers such as Gruner + Jahr and Spiegel-Verlag are pillars of the important media industry in Hamburg. In total, there are more than 120,000 enterprises.

Victoria Azarenka (Belarusian: Вікторыя Фёдараўна Азаранка, Russian: Виктория Фёдоровна Азаренко; born 31 July 1989) is a Belarusian professional tennis player. She is the current World No. 1 as of 28 May 2012.

She won the 2012 Australian Open singles title, becoming the first Belarusian player to win a Grand Slam in singles. Her other achievements include winning two mixed doubles Grand Slam titles, the 2007 US Open with Max Mirnyi and the 2008 French Open with Bob Bryan.

At age 16, Azarenka moved to Scottsdale, Arizona from Minsk, Belarus, to train. In this she was aided by National Hockey League goalie Nikolai Khabibulin and his wife, who is a friend of Azarenka's mother. In 2010 she briefly considered a break from the sport of tennis to focus on education, however, after a conversation with her grandmother she decided to continue playing. It is the inspiration from her grandmother that is regarded as the key for her continued developments in the sport. Azarenka is romantically involved with tennis player Sergei Bubka Jr, son of former Olympic gold medalist and World Champion, Sergey Bubka.

Vania King (traditional Chinese: 金久慈, simplified Chinese: 金久慈, Hanyu Pinyin: Jīn Jiǔcí) (born February 3, 1989 in Monterey Park, California, US) is a Taiwanese American female tennis player. King won both the 2010 Wimbledon Women's Doubles and 2010 US Open Women's Doubles titles with Kazakh partner Yaroslava Shvedova.

King's parents moved to the United States from Taiwan in 1982. She is the youngest of four children. Her brother Phillip was a four-time All-American at Duke University and two-time US junior champion.

In 2006 King won her only WTA singles title at the PTT Bangkok Open, a Tier III tournament with $200,000 in total prize money. She defeated Tamarine Tanasugarn in the final. On November 6, 2006, King achieved her career-high singles ranking of 50th overall.

In 2009, she reached the Mixed Doubles final at the French Open, alongside Brazilian player Marcelo Melo, losing to number 1 seeds Liezel Huber/Bob Bryan.

King lost in the second round of the 2009 Wimbledon Championships to No. 15 Flavia Pennetta. She played in the ladies doubles with Anna-Lena Grönefeld, losing in the quarter-finals to eventual champions Venus and Serena Williams.

Sara Errani (born April 29, 1987 in Bologna, Italy), nicknamed "Poco Gigante", is a professional female tennis player from Italy. On May 21, 2012, she reached a new career-high of no. 23 on the Tour rankings. On May 14, 2012, Errani became a top 10 doubles player and had a career high rank of World No. 8. She won five WTA titles in her career, and also has two ITF Titles.

At age 12 her father sent her to the Nick Bollettieri Tennis Academy in Florida. At 16 she moved to Valencia, in Spain, to be coached by Pablo Lozano and David Andres.

Errani competed in her first event at the $10,000 Cagliari event in her native country of Italy in 2002 where she lost to Sun Tiantian 6–1, 6–0. She continued to compete in the ITF, where her best performance of the year was a semifinal appearance in $10,000 Zaton. She continued to participate mainly on the ITF, where she won her first tournament 6–1, 6–4 over Lucia Jiminez in Melilla, Italy 2005.

Her first WTA title of her career was in the Internazionali Femminili di Palermo, where she defeated Mariya Koryttseva. On July 27, 2008, she captured her second career title in two weeks defeating Anabel Medina Garrigues, 6–3, 6–3. She has also won six doubles WTA titles.