In January, Viennot was preparing his first season as a full-time professional on the Spanish island of Lanzarote when during a training ride a car oversaw Cyril and other riders turning onto a main street. While the other riders managed to brake in time, the French athlete ran into the car almost at full speed. Viennot sustained several broken rips and a punctured lung. Doctors doubted whether a full recovery required to compete as a professional would be possible given the severity of the injuries. 6 months later, including a forced break from training, Viennot managed to win his first ever long distance race in Bolton, UK which is known as a tough course. After the swim, Viennot was in 10th place - 4:24 behind Englishman Harry Wiltshire. At the halfway point during the bike leg, the SCOTT athlete trailed strong cyclist Axel Zeebroek of Belgium by 5:18 but managed to cut the gap to 1:43 by the end of the bike split scoring the fastest time of the day on his brand new Plasma 5. Although Zeebroek managed to increase his lead during the first 15 kilometers of the marathon, Viennot stayed patient and didn't overpace. His strategy was rewarded on the second half of the closing marathon where Viennot passed the Belgian and kept the remaining competition at bay. In a total time of 8:44:10 the Frenchman won his first ever IM race only months after the near-fatal accident.