The day the French Open men's draw blew wide open Image source, Getty Images Image caption, Jannik Sinner had won 30 matches in a row before losing to Argentina's Juan Manuel Cerundolo in the French Open second round By BBC Sport tennis news reporter Not too long ago there were accusations that the men's singles at Grand Slams were becoming a predictable two-horse race. Jannik Sinner and Carlos Alcaraz had swept the previous nine Grand Slams between them, going head-to-head in three of those finals. When Alcaraz pulled out of the French Open with a wrist injury, it was expected to make for a tournament that lacked jeopardy, because who could stop Sinner? It felt as though the sweltering conditions in Paris could be the Italian top seed's biggest obstacle - and the 24-year-old wilted in the heat on Thursday. Sinner battled illness as Argentina's Juan Manuel Cerundolo - who deserves great credit for remaining calm - took advantage to win their second-round match 3-6 2-6 7-5 6-1 6-1.…