In the spring of 2011, Haidu was not selected in the team for the European Championships, but competed at some international meets. At the 2011 Glasgow World Cup, Haidu won the all around bronze after teammate Amelia Racea (gold) and Jessica Lopez (silver) and won the Brno mixed-pair event together with Cristian Bataga. In August 2011 she had a good showing at the Romanian Championships where she won the all-around bronze behind Ana Porgras and Amelia Racea, and silver on vault and uneven bars. She was then selected to the Romanian team for the 2011 World Championships in Tokyo. Here she helped the team to qualify (and finish in) fourth place; the top-eight finish secured the team a place at the 2012 Summer Olympics. Individually, Haidu qualified in 10th place for the all around final, but in the final she placed 18th after a fall on vault.