Simon & Nils Wogram Nabatov: duo of very versatile and often acclaimed young German trombonist Nils Wogram and Russian (but long resident in Cologne) keyboard lion Simon Nabatov.

Seems to be a common epithet for piano virtuosi.

so my favourite keyboard giant had played here as well
then my favourite keyboard giant must have played here as well

ik wil nog een optie toevoegen
een optie die veel gebruikt schijnt te worden in deze context

(Google: "keyboard giant(s)")

klavierleeuw

definitie van Dale:
klavierleeuw = pianist van bijzondere capaciteit, met een sterk persoonlijke, m.n. exuberante stijl van spelen, 'machtig' klavierspeler
de generatie klavierleeuwen uit het einde van de vorige eeuw

van Dale N - E = keyboard giant / keyboard star

ANTON RUBINSTEIN (1829-1894) Anton Rubinstein, from Russia, was one of the 19th-century keyboard giants

Ronald Smith is a very ordinary name for a rather extraordinary man. The pianist is best known for his campaign to give the French composer Charles-Valentin Alkan his rightful place in the canon of 19th-century keyboard giants; and yet he began as a composer, the piano only his second study.

http://www.old-lewesians.org.uk/goldmine/ronsmith.htm

Sand wrote that "only at the piano does he really open his heart." Yet, unlike Liszt, Thalberg and the other keyboard giants of his time whose fame derived from constant exposure, Chopin is known to have given only 30 public concerts in his entire life (and in many of those he was but one of several participating artists). He explained: "Concerts are never real music. You have to give up the idea of hearing in them the most beautiful things in art." Rather, Chopin's art blossomed in private, as he gave recitals before the aristocratic and cultural elite. He also played extensively before students and friends. Fontana recalled that Chopin would improvise for hours with "an inexhaustible torrent of precious materials out of which coalesced his finished compositions." Emile Galliard recalled that: "upon finishing a piece, Chopin would often stay sitting at the keyboard in silence, pursuing a dream of his own."

http://www.classicalnotes.net/classics3/chopinwaltzes.html