Lucas Arnold Ker
Lucas Arnold Ker is a retired professional tennis player from Argentina.
Arnold Ker started playing tennis in the Olivos Tenis Club of Buenos Aires, under coach Malcolm Campbell. He is the younger brother of Patricio Arnold.
He is right-handed and turned professional in 1994. He has played several times for the Argentine Davis Cup team, where he made his debut in 1997 against Venezuela. He was Roger Federer's opponent in the Swiss' first professional match in 1998, beating the 17-year-old future great in straight sets.
Cancer
In August 2006, he was diagnosed with testicular cancer. The testicle was removed, and he successfully underwent chemotherapy. In 2008, he was in remission and returned to playing professional tennis.Career titles
Doubles: 33 (15 wins, 18 losses)
| Result | W/L | Date | Tournament | Surface | Pertner | Opponents | Score |
| Win | 1. | Aug 1996 | San Marino, San Marino | Clay |  Pablo Albano | Mariano Hood Sebastián Prieto | 6–1, 6–3 |
| Loss | 1. | Oct 1996 | Marbella, Spain | Clay | Pablo Albano |  Lucas Arnold  Jack Waite | 7–6, 3–6, 4–6 |
| Win | 2. | Jun 1999 | Merano, Italy | Clay |  Jaime Oncins |  Marc-Kevin Goellner Eric Taino | 6–4, 7–6 |
| Win | 3. | Aug 1999 | San Marino, San Marino | Clay | Mariano Hood |  Petr Pála Pavel Vízner | 6–3, 6–2 |
| Win | 4. | Sep 1999 | Mallorca, Spain | Clay |  Tomás Carbonell | Alberto Berasategui Francisco Roig | 6–1, 6–4 |
| Win | 5. | Oct 1999 | Bucharest, Romania | Clay | Martín García | Marc-Kevin Goellner Francisco Montana | 6–3, 2–6, 6–3 |
| Loss | 2. | Feb 2000 | San Jose, U.S. | Hard |  Eric Taino | Jan-Michael Gambill Scott Humphries | 1–6, 4–6 |
| Win | 6. | Mar 2000 | Bogotà, Colombia | Clay | Pablo Albano | Joan Balcells Mauricio Hadad | 7-6, 1–6, 6–2 |
| Loss | 3. | Jul 2000 | Stuttgart, Germany | Clay | Donald Johnson | Jiří Novák David Rikl | 7–5, 2–6, 3–6 |
| Win | 7. | Feb 2001 | Viña del Mar, Chile | Clay | Tomás Carbonell | Mariano Hood Sebastián Prieto | 6–4, 2–6, 6–3 |
| Win | 8. | Feb 2001 | Buenos Aires, Argentina | Clay | Tomás Carbonell | Mariano Hood Sebastián Prieto | 5–7, 7–5, 7–6 |
| Loss | 4. | Feb 2002 | Viña del Mar, Chile | Clay | Luis Lobo | Gastón Etlis Martín Rodríguez | 3–6, 4–6 |
| Loss | 5. | Apr 2002 | Barcelona, Spain | Clay | Gastón Etlis | Michael Hill Daniel Vacek | 4–6, 4–6 |
| Loss | 6. | Jul 2002 | Kitzbühel, Austria | Clay | Àlex Corretja |  Robbie Koenig Thomas Shimada | 6–7, 4–6 |
| Win | 9. | Sep 2002 | Palermo, Italy | Clay | Luis Lobo | František Čermák Leoš Friedl | 6–4, 4–6, 6–2 |
| Loss | 7. | Feb 2003 | Buenos Aires, Argentina | Clay | David Nalbandian | Mariano Hood Sebastián Prieto | 2–6, 2–6 |
| Loss | 8. | Apr 2003 | Estoril, Portugal | Clay | Mariano Hood |  Mahesh Bhupathi Max Mirnyi | 1–6, 2–6 |
| Win | 10. | May 2003 | Valencia, Spain | Clay | Mariano Hood | Brian MacPhie Nenad Zimonjić | 6-1, 6–7, 6-4 |
| Loss | 9. | Jul 2003 | Båstad, Sweden | Clay | Mariano Hood |  Simon Aspelin Massimo Bertolini | 7–6, 0–6, 4–6 |
| Win | 11. | Sep 2003 | Palermo, Italy | Clay | Mariano Hood | František Čermák Leoš Friedl | 7-6, 6–7, 6–3 |
| Loss | 10. | Oct 2003 | Basel, Switzerland | Carpet | Mariano Hood |  Mark Knowles Daniel Nestor | 4–6, 2–6 |
| Win | 12. | Feb 2004 | Buenos Aires, Argentina | Clay | Mariano Hood | Federico Browne Diego Veronelli | 7–5, 6–7, 6–4 |
| Loss | 11. | Jul 2004 | Kitzbühel, Austria | Clay | Martín García | František Čermák Leoš Friedl | 3–6, 5–7 |
| Win | 13. | Sep 2004 | Bucharest, Romania | Clay | Mariano Hood | José Acasuso Óscar Hernández | 7–6, 6–1 |
| Win | 14. | Oct 2004 | Palermo, Italy | Clay | Mariano Hood | Gastón Etlis Martín Rodríguez | 7-5, 6–2 |
| Loss | 12. | Oct 2004 | Basel, Switzerland | Carpet | Mariano Hood | Bob Bryan Mike Bryan | 6–7, 2–6 |
| Loss | 13. | Apr 2005 | Valencia, Spain | Clay | Mariano Hood |  Fernando González Martín Rodríguez | 4–6, 4–6 |
| Win | 15. | May 2005 | Sankt Pölten, Austria | Clay | Paul Hanley | Martin Damm Mariano Hood | 6–3, 6–4 |
| Loss | 14. | Aug 2005 | Sopot, Poland | Clay | Sebastián Prieto |  Mariusz Fyrstenberg Marcin Matkowski | 6–7, 4–6 |
| Loss | 15. | Apr 2006 | Estoril, Portugal | Clay | Leoš Friedl | Lukáš Dlouhý Pavel Vízner | 3–6, 1–6 |
| Loss | 16. | Jul 2006 | Amersfoort, Netherlands | Clay |  Christopher Kas | Alberto Martín Fernando Vicente | 4–6, 3–6 |
| Loss | 17. | Jul 2008 | Kitzbühel, Austria | Clay |  Olivier Rochus | James Cerretani Victor Hănescu | 3–6, 5–7 |
| Loss | 18. | Feb 2009 | Costa do Sauípe, Brazil | Clay | Juan Mónaco | Marcel Granollers Tommy Robredo | 4–6, 5–7 |