Resuming his career after being interned as an enemy alien during the Great War, Spivakovsky proceeded from triumph to triumph and was hailed as a master interpreter of all musical styles. He was acclaimed in particular as an exceptional exponent of The Three Bs (Bach, Beethoven and Brahms), after performing a monumental series of historical concerts with Wilhelm Furtwängler and the Berlin Philharmonic Orchestra, under the moniker Bach to Brahms. Thereafter he often opened recitals with major Bach works, including his own signature variation of the dramatic Busoni transcription of the Chromatic Fantasy and Fugue.

Critics around the world highlighted the brilliance of these performances. From Aftenposten in Oslo: "The Russian pianist who, yesterday, gave his first concert in the Aula, has a musical perception and technique of the highest perfection. This was already evident in the first number, Bach's Chromatic Fantasia and Fugue where the complicated polyphony was expressed with the greatest clarity." The Argus in Melbourne: "There was an imposing display of technical skill at the beginning of the evening in the Bach Chromatic Fantasie and Fugue. It was a revelation of rhythmic vitality, with great power and intensity in the climax. Technique can be either the letter that deadens or the spirit which vivifies. Spivakovsky, in his Bach playing, shows that with him the spirit is the thing." And the Sydney Morning Herald: "… beautifully interpreted … the arpeggio passages excited … an awed anticipation as if the curtains before the future life were about to be lifted; and the vivacious charm and leaping grace of the fugue once more delighted the ear, as must ever be the case at the hands of truly accomplished artists."

Critics also appreciated the signature stamp Spivakovsky put on this mighty work. The Neue Preußische Zeitung in Berlin: "On a pedestal stands pianist Jascha Spiwakowski ... he filled Bach's Chromatic Fantasy and Fugue with vital substance." The Telegraph in Sydney: "He opened with the brilliant Chromatic Fantasie and Fugue in D Minor of Bach … The fantasie is like a noble recitative embroidered with rich cadenzas, and then the fugue enters stately in its calm first utterance, and passing through ingenious elaborations that call for the highest executive skill. Spivakovsky gave it more than this; he added touches of romance and reflectiveness that bespoke the musician. The audience was wildly delighted with the performance and brought the player back half a dozen times.” And the Sunday Times in Perth: "As his opening number the artist selected the Bach Chromatic Fantasia and Fugue, which he invested with a rare charm. Delicacy of expression, a full appreciation of tonal effects, and a pleasing display of the figures of the composition marked the performer as a worthy exponent of this master, a position which only the highly gifted can hope to reach. The fine declamation of the massive climax in the fugue revealed the extraordinary technique as well as penetrating perception of the artist."

From his earliest performances, critics noted the distinctive Spivakovsky sound signature, however they struggled to translate it into words. During his wildly successful return tour of the United Kingdom in 1921, a leading London critic printed: "Of all the pianists I have heard in recent years, no one seems to have more temperamental affinity with the very greatest than Jascha Spivakovsky. There is in his art something personal and exclusive, rare and imaginative, that cannot be defined in English, liberal as it is in words of fine meaning. I can only sit back after hearing him and badly express my appreciation by calling him a genius."

The following year, The New Zealand Times: "GENIUS OF HIGHEST RANK: Players come and players go, but there are very few artists in the world whom one would care to say are real geniuses. Of these few one has not the least hesitation in saying that Spivakovsky is one of the rarest. He has to be heard before he can be understood. Mere wealth of verbiage gives little real idea of the man as the artist, the genius, the virtuoso." And the Brisbane Courier: "A virtuoso gifted by shining genius. His distinguishing characteristics are difficult to describe, because he combines the best qualities of several different schools. A superb technique – one may say, a perfected technique – extraordinary brilliancy, great power of tone, and remarkable delicacy of touch, combine to make his playing a delight to the ear, while his sense of rhythm and the delicious felicity of his phrasing are equally conspicuous. All these traits are embellished with a rare faculty which enables him to pass from one stupendous composition to another, or from lightest shades to darkest gloom, investing each with the composer's individuality, and at the same time preserving his own strong personality." Then the next year, the Breslauer Morgen-Zeitung: "Who will explain this wonder-genius?"

Eventually the legendary British critic Sir Neville Cardus coined the descriptor crystal piano-playing to characterise the Spivakovsky sound signature, after hearing a positively radiant performance of the Mozart piano concerto in A Major. His wife, Lady Edith, had telegrammed Spivakovsky her own summation after hearing him perform the same work a few years earlier: "Hearty congratulations on the best Mozart playing have ever heard."

Crystal piano-playing shines through this equally radiant performance of the Sonata in F. From reviews of Australian performances, The Sun in Sydney: "There was crystal sparkle in the recitalist's performance of Mozart's F major Sonata, his pausation as well as swiftness in descending runs of the last movement being a feature." And The Age in Melbourne: "With so many pianists essaying sonatas on Mozart, it was a rare pleasure to hear the recitalist declare the master's excellence free from blemish and with the charm associated with his name."

Spivakovsky first became world famous for performing Romantic repertoire as a child prodigy. The Dominion reported excitedly to the New Zealand public in 1916: "A Young Genius: for several seasons the Berlin critics and public have watched with unusual interest the development of Jascha Spiwakowski, a youthful Russian pianist, who astonished the musical world as a prodigy. He has now outgrown the prodigy phase and appears as a fully-fledged artist. It is doubtful if his teacher, Moritz Meyer-Mahr, has ever had another such talent in his twenty-five years’ experience as a pedagogue. It makes no difference whether he plays Brahms, Chopin or Liszt, he always surprises with the maturity and depth of his conception and the finish and brilliancy of his execution." His repertoire then expanded rapidly during his youth prodigy years, however he remained best known for the Romantics until the Great War. Walter Niemann declared in his 1919 book Meister des Klaviers: "Jascha Spiwakowski has achieved capital G Greatness in Berlin … the child prodigy has now become a youth prodigy: spirited, full-blooded, potent, with greatly sensitive and instinctive musicality, supreme technical talent and an especially fine appreciation of Chopin, Schumann and the Romantics."

By the time he was a young man, his repertoire encompassed Baroque to the most modern and he was ranked one of the greatest performers in the world. After 3,000 clamouring Londoners had to be turned away from a sold-out Royal Albert Hall, the Daily Mail: "One of the greatest pianists of our time." During his Bach to Brahms tour de force across Germany, the Hamburgischer Correspondent: "The strongest piano talent I have encountered in the course of the last decade." And during his phenomenonally successful inaugural tour of Australia in 1922, Table Talk: "Jascha Spivakovsky, young as he is, ranks above any of the pianists we have heard in recent years and is probably the most satisfying, all-round performer this generation has heard. His interpretations have soul, that greatest asset, and a glorious mellow beauty of song-like tone which is enthralling."

Spivakovsky performed many Chopin works during this Australian tour and electrified audiences with the fire and poetry of his interpretations. Reviews from The Brisbane Courier: "Mr Spivakovsky left no doubt in the minds of his admiring hearers that he was king in the realm of Chopin." And The Argus in Melbourne: "…extraordinary command over multitudinous shades of dynamic tone and colour, from a cankling fortissimo to a pianissimo of melting softness … Chopin's adorable Fantasie Impromptu, not too often played nowadays, was invested with the most delightful grace." The great Australian coloratura soprano, Dame Nellie Melba, penned Spivakovsky her own review after his first Melbourne concert: "I consider you one of the greatest pianists in the world."

Spivakovsky delivers this stunning performance with the hallmarks of his immortal musical grandfathers, combining the bravura technique and pithy expression of Liszt with the golden tone and overwhelming passion of Anton Rubinstein. These elements he expertly marshalls according to his own powerful interpretive vision, in order to capture the full gravitas and beauty of this work. In the Funeral March movement for example, he takes the standpoint of Chopin as observer, midway between the church and the gravesite, building a dramatic crescendo as the procession approaches. This culminates in a magnificent key-change from minor to major as the procession passes the composer. A diminuendo marks the approach of the procession to the gravesite, followed by the beautiful cantilena of the singing over the grave. Then the crescendo and diminuendo are repeated as the procession returns to the church. In the final movement, Chopin looks to the lonely gravesite and visualises what Spivakovsky referred to as "the wind mixing the souls of the departed."

After astounding performances of this work in 1933, The News in Adelaide declared: "We have heard many performances of the Chopin Funeral March Sonata, but that by Jascha Spivakovsky was on a pinnacle apart. His manipulation of the scherzo was amazing, and he plumbed the very depths of emotional playing. The final presto was ephemeral, fleeting and eerie." The Advertiser echoed: "I have never heard a reading to touch it, often as it is played. Technical equipment and conception of the first and last movement were what we have been waiting for. Beyond even these dizzy heights soared his Scherzo and his Funeral March … The Scherzo was never so strong and compelling and he roamed at will through the sunlit fields of its trio. From the march, the minor section of which is terrific in its hopelessness, the cantilena shone like a pure star. The song and the background were the limit of beauty."

In the postwar period, Spivakovsky mentored younger pianists including William Kapell, Julius Katchen and Shura Cherkassky and guided many others such as Simon Barere, Joseph Seiger and Paul Badura-Skoda. During his tours of Australia in the late Forties and early Fifties, Kapell often visited Spivakovsky at his riverside mansion in Melbourne and they developed a strong rapport. Kapell would practise on the pianos, paint on the riverbank and ask the maestro all manner of questions regarding musical interpretation and performance. During his tour in 1953, he also sought advice on how to handle the Australian critics, some of whom had been shockingly critical of his performances.

After a particularly stinging review by the chief music critic for a leading Australian newspaper, Spivakovsky telephoned the author to offer his opinion that Kapell was a very fine artist and the critiques were overly harsh. However the author was adamant in his views, leading Spivakovsky to recommend a different strategy. He advised Kapell that because it was well known that this critic would often quietly leave concerts during the interval, he should change one of the pieces in the second half of the programme at his next Sydney concert, informing the audience of the change after the interval. Kapell initially protested "But Jascha, you can’t do that!" however became convinced after Spivakovsky calmly explained how to proceed. After the concert, a furore erupted in Australian musical circles, when it emerged the critic had unfavourably reviewed the piece Kapell substituted out of the programme.

Kapell spent the last day of this tour with the Spivakovsky family, at one point surprising Jascha's son by displaying his palm and prophetically stating: "See my life-line stops halfway. I shouldn't be here." Then through the night until daybreak, Kapell and Spivakovsky took turns playing different works and discussing music. When the maestro played the third movement of Chopin's Funeral March sonata, his young American companion stated with reverence: "Aww Jascha, that's beautiful! You're a poet." Prior to boarding his tragically ill-fated return flight to San Francisco, Kapell voiced his displeasure with Australian critics to a throng of press reporters at the airport: "Much of what is written here is uninformed, false and malicious … This is goodbye forever. I shall never return. I mean what I say."