DuckCorp Dico

Found one definition

1.                 From Japanese-English FreeDict Dictionary ver. 0.1:
                   
   
   
                   
                     
    (ateji (phonetic) reading)  [ichi1]  流石 /(en)tʃˈaɪniːz(ja)lˈe̞tə (en)tʃˈaɪniːz(ja)lˈe̞tə/, 遉 /(en)tʃˈaɪniːz(ja)lˈe̞tə/,  [ichi1] さすが /säsˈɯᵝɡä/
   1. (adjectival nouns or quasi-adjectives (keiyodoshi))
    (adverb (fukushi))
    (nouns which may take the genitive case particle `no')
            Note: word usually written using kana aloneas one would expect
   2.
            Note: word usually written using kana alonestill, all the same
   3.
            Note: word usually written using kana alone (as さすがの〜も)
   even... (e.g. "even a genius...")