Guillaume Rufin
Guillaume Rufin is a French professional tennis player. His highest singles ranking is World No. 81, achieved in September 2013. He received a wildcard into the 2009 French Open, his ATP-tier debut. In the first round, one day before his 19th birthday, he beat Eduardo Schwank, 6–1, 6–3, 6–3.
Rufin achieved another landmark in his young career on 25 October 2009, when he won the Florianapolis Challenger title in Brazil, beating Pere Riba in the final, 6–4, 3–6, 6–3.
He reached the quarterfinals of the 2010 Open 13 in Marseille. In the first round, Rufin defeated lucky loser Laurent Recouderc, 7–5, 4–6, 7–6. He followed this up by defeating Yannick Mertens of Belgium, 6–3, 2–6, 6–2. He eventually fell to World No. 92 Mischa Zverev, 7–5, 6–7, 6–3.
Rufin received a wildcard into the 2010 US Open and defeated Leonardo Mayer in four sets before losing to Paul-Henri Mathieu in the second round.
Challenger finals
Singles: 7 (3–4)
| Outcome | No. | Date | Tournament | Surface | Opponent | Score |
| Winner | 1. | 25 October 2009 | Florianópolis, Brazil | Clay |  Pere Riba | 6–4, 3–6, 6–3 |
| Runner-up | 1. | 15 July 2012 | Timișoara, Romania | Clay |  Victor Hănescu | 0–6, 3–6 |
| Runner-up | 2. | 7 October 2012 | Quito, Ecuador | Clay |  João Souza | 2–6, 6–7 |
| Winner | 2. | 21 October 2012 | Villa Allende, Argentina | Clay | Javier Martí | 6–2, 6–3 |
| Runner-up | 3. | 28 October 2012 | Buenos Aires, Argentina | Clay |  Diego Schwartzman | 1–6, 5–7 |
| Winner | 3. | 28 July 2013 | Oberstaufen, Germany | Clay |  Peter Gojowczyk | 6–3, 6–4 |
| Runner-up | 4. | 7 September 2014 | Brașov, Romania | Clay |  Andreas Haider-Maurer | 3–6, 2–6 |
Doubles: 1 (0–1)
| Outcome | No. | Date | Tournament | Surface | Partner | Opponents | Score |
| Runner-up | 1. | 7 January 2012 | Nouméa, New Caledonia | Hard |  Axel Michon |  Sanchai Ratiwatana Sonchat Ratiwatana | 0–6, 4–6 |