Take this cadence-ending treble line.
It’s not too hard to imagine this bass line, with an implied Neapolitan chord, underneath it.
Now take this cadence-ending bass line.
It’s not too hard to imagine this treble line, with an implied secondary dominant, above it.
By themselves, these lines imply staples of chromatic harmony. But toward the end of a chorus from La forza del destino ("Nella guerra, è la follia"), Verdi puts them together.
On the one hand, Verdi puts a root-position G-major chord in C-sharp minor music: ping! On the other hand, the stylistically normal soprano and bass lines -- enharmonics aside -- fly right by, sotto il radar. Viva Verdi indeed.