While he was still a student at the Conservatoire, Duruflé won two important competitions sponsored by Les Amis de l’Orgue, one in 1929 and the other in 1930. The first assured his renown as an organist and improviser, and the second established his reputation as a composer of distinction.

Upon the urging of Vierne, Duruflé participated in the competition in organ performance and improvisation that was sponsored at the Église de l’Étoile, in June of 1929, by Les Amis de l’Orgue, the association of professional organists established in 1927. For the preliminary round the contestants had to perform the Toccata, Adagio, and Fugue, BWV 564, of Bach, and improvise an ornamented choral on “a theme from the Catholic liturgy.” They then had to improvise a symphonic paraphrase on the same theme, in a form of the contestant's choice. For the second round the contestants had to be prepared to play any of eight pieces, including the fourth trio sonata of Bach, the Choral in E Major of Franck, the first movement of Widor's Symphonie gothique, the third part of Tournemire's Triple Choral and the final movement of Vierne's Third Symphony. It was the lastnamed piece that the jury asked of Duruflé. Then he was asked to play an improvisation symphonique, including a prelude and fugue on a given theme, and then a free improvisation on two given themes in the form of an Allegro, Adagio, and Finale. Serving on the jury were Vincent d’Indy, Charles Tournemire, Louis Vierne, Joseph Bonnet, Alexandre Cellier, and André Marchal.

Duruflé was named the winner on June 29 and was awarded the prize of 5000 francs. Louis Vierne, who undoubtedly took considerable pride in his pupil's success, remembered Duruflé's “blazing organ competition” as the event that established him as an organist and improviser. It was indeed a monumental achievement.

The following year, Les Amis de l’Orgue sponsored a competition in composition, on June 20, 1930 at the Institut des jeunes aveugles. A preliminary round eliminated nine contestants, including André Fleury. Joseph Ermend- Bonnal, Henriette Roget, and Duruflé proceeded to the final round, all of whom had been students of Tournemire, a fact that put the maître in an awkward position as a member of the jury.