The Williams sisters are two professional American tennis players: Venus Williams (b. 1980), a seven-time Grand Slam title winner (singles), and Serena Williams (b. 1981), twenty-three-time Grand Slam title winner (singles), both of whom were coached from an early age by their parents Richard Williams and Oracene Price.
 There is a noted professional rivalry between them – between the 2001 US Open and the 2017 Australian Open tournaments, they met in nine Grand Slam singles finals.
 They became the first two players, female or male, to play in 4 consecutive grand slam singles finals from the 2002 French Open to the 2003 Australian Open; Serena famously won all 4 to complete the first of two "Serena Slams".
 Between 2000 and 2016, a 17-year span, they collectively won 12 Wimbledon singles titles (Venus won 5 and Serena won 7).
 By winning the 2001 Australian Open women's doubles title, they became the 5th pair to complete the Career Doubles Grand Slam and the only pair to complete the Career Doubles Golden Slam.
 At the time, Venus and Serena were only 20 and 19 years old, respectively.
 Since then they have gone on to add another two Olympic gold medals in the 2008 Beijing Olympics and the 2012 London Olympics.
 Nearly a decade later, the duo would go on to win 4 consecutive grand slam doubles titles from 2009 Wimbledon through 2010 Roland Garros, which would catapult them to co-No.
 1 doubles players on 7 June 2010.
 Two weeks later, on 21 June 2010, Serena would hold the No. 1 singles ranking and Venus would be right behind her at No. 2 in singles.
 Their most recent grand slam doubles titles came at the 2012 Wimbledon & 2016 Wimbledon events.
 They remain very close, often watching each other's matches in support, even after one of them has been knocked out of a tournament.
Serena Williams's 2009 tennis season officially began at the 2009 Medibank International Sydney.
 Williams finished the year ranked world no. 1 for the second time in her career, having played in 16 tournaments, more than any other year.
 She also broke the record previously set by Justine Henin for the most prize money earned by a female tennis player in one year, with Williams earning $6,545,586.
 In doubles, she finished the year ranked world no. 3, despite playing only six tournaments as a pair.
 She won five Grand Slam titles, putting her total Grand Slam titles at 23.
Jonathan Dario "Yoni" Erlich (Hebrew: יונתן דאריו "יוני" ארליך‎ ‎ , born in Buenos Aires, Argentina, April 5, 1977) is a professional Israeli tennis player.
 He plays doubles, primarily.
Philipp Oswald (born 23 January 1986) is an Austrian professional tennis player who primarily plays doubles events on the ATP World Tour.
 On 7 December 2009, he reached his highest ATP singles ranking of world no. 206, whilst his highest doubles ranking of no. 37 was reached on 23 February 2015.
Bartolomé "Tomeu" Salvá Vidal (born November 20, 1986 in Majorca, Balearic Islands) is a Spanish tennis player.
 While he plays singles, he is also a doubles player, who partners with friend Rafael Nadal.
 In 2007 at the Open Seat Open in Barcelona, Spain, Salvá and Nadal made it to the final (on red clay, the surface that Nadal excels on), defeating Jonathan Erlich and Andy Ram (both ranked 13) and Mark Knowles and Daniel Nestor (both ranked fifth) in straight sets on both occasions.
 They made it to the finals, but Alexander Waske and Andrei Pavel defeated them 6–3, 7–6 (1).
The 2012 Aircel Chennai Open was a 2012 ATP World Tour tennis tournament, played on outdoor hard courts.
 It was the 17th edition of the only ATP tournament taking place in India and took place at the SDAT Tennis Stadium in Chennai, India.
 It was held from 2 to 8 January.
 Stanislas Wawrinka was the defending singles champion coming into the tournament but was knocked out in the quarterfinals.
 Former champion Marin Čilić was originally in the field as the 4th seed before pulling out with a patellar tendon injury.
 Finally, fourth seed Milos Raonic from Canada defeated world no. 9 and top seeded Serb Janko Tipsarević to win only his second ATP title.
 Raonic became the first player since Roger Federer in 2008 to win an ATP title without losing a serve.
 The doubles title went to the Indo-Serb pair of Leander Paes and Janko Tipsarević after they defeated the Israeli pair of Jonathan Erlich and Andy Ram.
David Sherwood is a tennis coach and former British tennis player.
 In his only live Davis Cup match, Sherwood played doubles with Andy Murray beating the Israeli World No 4 doubles team of Jonathan Erlich and Andy Ram,
Althea Gibson (August 25, 1927 – September 28, 2003) was an American tennis player and professional golfer, and the first black athlete to cross the color line of international tennis.
 In 1956, she became the first person of color to win a Grand Slam title (the French Open).
 The following year she won both Wimbledon and the U.S. Nationals (precursor of the U.S. Open), then won both again in 1958, and was voted Female Athlete of the Year by the Associated Press in both years.
 In all, she won 11 Grand Slam tournaments, including six doubles titles, and was inducted into the International Tennis Hall of Fame and the International Women's Sports Hall of Fame.
 "She is one of the greatest players who ever lived," said Robert Ryland, a tennis contemporary and former coach of Venus and Serena Williams. "
Martina couldn't touch her.
 I think she'd beat the Williams sisters."
 In the early 1960s she also became the first black player to compete on the women's professional golf tour.
Serena Jameka Williams (born September 26, 1981) is an American professional tennis player.
 The Women's Tennis Association (WTA) has ranked her world No. 1 in singles on eight occasions, from 2002 to 2017.
 She became the world No. 1 for the first time on July 8, 2002.
 On the sixth occasion, she held the ranking for 186 consecutive weeks, tying the record set by Steffi Graf for the most consecutive weeks as world No. 1 by a female tennis player.
 In total, she has been world No. 1 for 319 weeks, which ranks her third in the Open Era among female tennis players.
 Some commentators, players and sports writers regard her as the greatest female tennis player of all time.
Roy Stanley Emerson (born 3 November 1936) is an Australian former World number one tennis player who won 12 Major singles titles and 16 Grand Slam tournament men's doubles titles.
 He is the only male player to have completed a Career Grand Slam (winning titles at all four Grand Slam events) in both singles and doubles.
 His 28 major titles are an all-time record for a male amateur player.
 Emerson is the first male player to win each amateur major title at least twice in his career.
 He is one of only eight men to win all four majors in his career.
 He was the first male player to win 12 majors.
 Along with Novak Djokovic, he is one of only two male players to win six Australian Championships.
 He won five of them consecutively (1963–67).
 His 12 wins have since been surpassed.
 Emerson is one of only five tennis players all-time to win multiple slam sets in two disciplines, only matched by Margaret Court, Martina Navratilova, Frank Sedgman and Serena Williams.

Question: Which tennis player primarily plays doubles, Jonathan Erlich or Serena Williams?
Answer: Jonathan Dario "Yoni" Erlich