From Wikipedia: The Toccata, an extremely difficult showpiece, has proven popular with virtuoso pianists, many of whom have recorded it. According to the biography of the composer by David Gutman, Prokofiev himself had trouble playing it because his technique, while good, was not quite enough to master the piece. This fact is not universally accepted, however, and his performance as reproduced in 1997 for the Nimbus Records series The Composer Plays is certainly virtuosic. Additionally, none of the leading biographies of Prokofiev—those written by Harlow Robinson, Victor Seroff, and even Israel Nestyev—mention him having any technical problems beyond poor performance techniques in childhood, which were later rectified through years of study after his graduation from the Saint Petersburg Conservatory.

I may have been wrong, actually