Question: Who was ranked World No. 4 in 1965, Cliff Drysdale or Roberta Vinci?

Context paragraphs:
Marta Domachowska: Marta Domachowska (; born 16 January 1986 in Warsaw) is a Polish retired professional tennis player ranked World No. 37 in singles (2006) and World No. 62 in doubles (2006).  She reached 2008 Australian Open fourth round in singles and won 2006 Canberra International in doubles with Roberta Vinci.  She also reached three WTA Tour singles finals at 2004 Hansol Korea Open (lost to Maria Sharapova), 2005 Internationaux de Strasbourg (lost to Anabel Medina Garrigues) and 2006 U.S. National Indoor Tennis Championships (lost to Sofia Arvidsson).  She was 2003 Australian Open finalist in girls' singles, represented Poland at the 2008 Summer Olympics and was member of Poland Fed Cup team.  Domachowska was the best female Polish tennis player after Magdalena Grzybowska's retirement and before Agnieszka Radwańska's successes.

2011 Barcelona Ladies Open – Doubles: Sara Errani and Roberta Vinci were the defending champions, but Roberta Vinci chose not to continue her performance before the quarterfinals.

Roberta Vinci: Roberta Vinci (] ; born 18 February 1983) is an Italian tennis player.  Up until 6 April 2015, she held the position of World No. 1 in doubles, while reaching a career-high of World No. 7 in singles in May 2016.  She is the fourth Italian woman to have reached the top 10 in singles, together with Flavia Pennetta, Francesca Schiavone and Sara Errani.  At 33 years and 4 days old, she is also the oldest ever player to make her first appearance in the Top 10.

Association of Tennis Professionals: The Association of Tennis Professionals (ATP) was formed in September 1972 by Donald Dell, Bob Briner, Jack Kramer, and Cliff Drysdale to protect the interests of male professional tennis players.  Drysdale became the first President.  Since 1990, the association has organized the worldwide tennis tour for men and linked the title of the tour with the organization's name.  In 1990 the organization was called the ATP Tour, which was renamed in 2001 as just ATP and the tour being called ATP Tour.  In 2009 the name was changed again and is now known as the ATP World Tour.  It is an evolution of the tour competitions previously known as Grand Prix tennis tournaments and World Championship Tennis (WCT).

Jack Kramer: John Albert Kramer (August 1, 1921 – September 12, 2009) was an American tennis player of the 1940s and 1950s.  A World No. 1 player for a number of years, and one of the most important people in the establishment of modern men's "Open"-era tennis, he was the leading promoter of professional tennis tours in the 1950s and 1960s.  He was a relentless advocate for the establishment of Open Tennis between amateur and professional players.  An International Tennis Federation (ITF) proposal to introduce Open tennis lost by five votes in 1960, but became a reality in 1968.  In 1970, he created the Men's Grand Prix points system.  In 1972, he helped found the Association of Tennis Professionals (ATP) with Donald Dell and Cliff Drysdale, and was the first Executive Director.  He was unpaid at his request.  In that role, he was the leader of an ATP boycott of Wimbledon in 1973, for the banning of Nikola Pilić from the tournament.

1968 Suisse Open Gstaad: The 1968 Suisse Open Gstaad was a combined men's and women's professional tennis tournament played on outdoor clay courts in Gstaad, Switzerland.  It was the 23rd edition of the tournament and was held from July 22 through July 28, 1968.  Cliff Drysdale and Annette du Plooy won the singles titles.

1965 U.S. National Championships – Men's Singles: Manuel Santana defeated Cliff Drysdale 6–2, 7–9, 7–5, 6–1 in the final to win the Men's Singles tennis title at the 1965 U.S. National Championships.

Cliff Drysdale: Eric Clifford Drysdale (born 26 May 1941, Nelspruit, South Africa) is a former top-ranked professional tennis player of the 1960s and early 1970s who became a well-known tennis announcer.  He was one of the Handsome Eight, a group of players signed by Lamar Hunt in 1968 for the newly formed professional World Championship Tennis (WCT) group.  He became President of the Association of Tennis Professionals (ATP) when it was formed by Jack Kramer, Donald Dell, and himself in 1972.  Drysdale was ranked World No. 4 in 1965 by Lance Tingay of The Daily Telegraph.

Flavia Pennetta: Flavia Pennetta (] ; born 25 February 1982) is a retired Italian professional tennis player and Grand Slam-champion in both singles and doubles.  She became Italy's first top-10 female singles player on 17 August 2009 and the first Italian to be ranked world No. 1 in doubles on 28 February 2011.  She became a Grand Slam singles champion, winning the 2015 US Open by defeating her childhood friend Roberta Vinci in the first all-Italian Grand Slam final .

Red Ledges: Red Ledges is a country club located in Heber City, Utah.  It is the first club in the world that has a Jack Nicklaus Signature golf course, Cliff Drysdale tennis academy and Jim McLean Golf School.  It also contains a luxury master-planned community.

Supporting paragraphs: Cliff Drysdale Roberta Vinci
Answer: Eric Clifford Drysdale