When did the Ateneo–La Salle rivalry begin?
Ateneo–La Salle rivalry
La Salle Greenies defeated the Ateneo Blue Eaglets in the 1939 NCAA Junior Championship. Ateneo High School and De La Salle Santiago Zobel School (DLSZ) met twice in the UAAP juniors' basketball finals; in 2007 in which DLSZ won in two games dethroning the Eaglets in the process, and in 2009 in which the Blue Eaglets won the best-of-three series, 2–1.  In addition, the Junior Archers weren't able to defend their 2005 championship due to their suspension along with their seniors' counterparts.[20]