At the age of seven, he learned piano with Professor Avreliana Hryhorovycha Rubbakha (1895—1975), a student of Felix Blumenfeld, who also taught Symona Barera and Volodymyra Horovytsya. Rubbakha was the first serious teacher for Kapustin, and together they worked hard for 11 years. While he was learning, Kapustin fully went through the path of becoming a pianist of the classical type, playing works by Bach, Clementi, Scarletti, Liszt, Beethoven, and passing various scales, arpeggios, etc. on technical tests.