The Virginia Slims Circuit was a tennis tour consisting of a group of originally nine female professional players.
 Formed in 1970, the Virginia Slims Circuit eventually became the basis for the later named WTA Tour.
 The players, dubbed the "Original 9", rebelled against the United States Lawn Tennis Association (USLTA) due to the wide inequality between the amount of prize money paid to male tennis players and to female tennis players.
Athletic DNA (ADNA) is an American sports apparel company.
 Founded in Seattle in 2007, ADNA began by training young tennis athletes, which evolved into sponsoring Select Junior Tennis players, and then expanded to manufacturing clothing for youth and adult tennis players.
 ADNA has since spread to professional tennis, and currently sponsors players on the ATP Tour & WTA Tour.
Oliver Marach (born 16 July 1980) is an Austrian professional tennis player.
 His highest ATP singles ranking is world No. 82, which he reached on August 7, 2005.
 His career high in doubles is world No. 8, set on October 18, 2010.
Viktor Galović (born 19 September 1990 in Nova Gradiška) is a Croatian tennis player.
 Galović has a career high ATP singles ranking of 224, achieved on 17 July 2017.
 Galović made his ATP main draw singles debut at the 2014 Bet-at-home Cup Kitzbühel where he qualified for the main draw, defeating Philipp Davydenko, Lukáš Dlouhý and Antonio Veić en route.
 In the main draw he lost to Albert Ramos-Viñolas in three sets in the first round.
Donald Dell (born June 17, 1938 in Savannah, Georgia, United States) is an attorney and was a professional tennis player, U.S. Davis Cup captain, and administrator.
 Dell was one of the first professional sports agents, having represented professional tennis players Arthur Ashe, Stan Smith, Jimmy Connors, and Ivan Lendl during pro tennis' golden age (1975 to 1985).
 He was also the founder of Professional Services (ProServ), one of the nation's first sports marketing firms established in 1970 with co-founder, Frank Craighill, a fellow law partner.
 His younger brother, Dick, worked for ProServ managing US Open champion Gabriela Sabatini, and played Number One Singles for the University of Michigan.
 He was Big Ten #1 Singles Champion in 1969.
The "Challenge of Champions" was created to be one of the richest prize money tennis events in the world.
 Created by Leo E. Fenn III in 1985 as an Invitation Only Tennis Tournament which would feature daily matches which were the equivalent to the Finals of the US Open or Wimbledon.
 It was usually held before the Masters and invited only the top eight men's tennis players in the world according to their rankings on the ATP poll.
 In 1985, creator & founder 24-year-old Leo E. Fenn III partnered with 28-year-old Mark Myden to form a company called Special Events Productions.
 SEP produced the "Challenge of Champions" Tournament which became a major player in professional tennis.
 These two entrepreneurs became the youngest producers in history of professional tennis.
 Leo & Mark acquired major fortune 500 corporate sponsors such as AT&T, VISA, Cadillac, Fila Sportswear, DeBeers Diamonds as well as negotiated two days of live weekend television coverage on NBC.
 Their title sponsorship package sold to AT&T was the largest single vent sponsorship package in professional tennis that year.
 Leo negotiated with the brand new Thomas Mack Center Arena in Las Vegas to host the inaugural event.
 The event rights were eventually sold to Pro Serve and concluded following the 1989 Challenge.
Tommy Robredo and Marcel Granollers were the defending champions.
 Robredo chose to compete in the 2010 ABN AMRO World Tennis Tournament instead.
 Granollers partnered with Pablo Cuevas, and they won in the final 7–5, 6–4 against Łukasz Kubot and Oliver Marach.
Mate Pavić (born 4 July 1993) is a Croatian professional tennis player specialising in doubles.
 Mate won the 2016 US Open mixed doubles title in partnership with Laura Siegemund, and reached the 2017 Wimbledon Championships men's doubles finals partnering Oliver Marach.
Lukáš Dlouhý (born 9 April 1983) is a professional Czech tennis player on the ATP Tour.
 A doubles specialist, Dlouhý reached a career-high ranking of World No. 5 in June 2009.
Rod Laver defeated Tony Roche 6–3, 6–4, 6–2 in the final to win the Gentlemen's Singles title at the 1968 Wimbledon Championships.
 It was Laver's third Wimbledon title, and his seventh grand slam overall.
 This was the first year when professional tennis players were allowed to compete at the Wimbledon Championships.
 Previously only amateur tennis players could compete.

Question: Were both Oliver Marach and Lukáš Dlouhý professional tennis players?
Answer: yes