alone(p), unique, unequaled, unequalled, unparalleled(adj)

radically distinctive and without equal

"he is alone in the field of microbiology"; "this theory is altogether alone in its penetration of the problem"; "Bach was unique in his handling of counterpoint"; "craftsmen whose skill is unequaled"; "unparalleled athletic ability"; "a breakdown of law unparalleled in our history"

unequalled(Adjective)

Without equal; unmatched.