Mexico City Returns To ATP Challenger Tour From the same organizers of the ATP World Tour events in Acapulco and Los Cabos, the ATP Challenger Tour returns to Mexico City for the first time since 2007, with the CDMX Open. Based in the Chapultepec Sports Club, one of the most important venues in the history of Mexican tennis, the tournament is held in mid-April, with a prize money of $100,000.