Duggan is a damn good QB and a good runner, but he is not nearly as elusive as Stroud. The GA DL were not fast enough to tackle Stroud even when he was completely cornered, so finally Smart threw some fast LBs and DBs into the blitz.
The key to the game was Strouds incredible elusiveness in the pocket.
IMO this game the GA DL will be able to surround and tackle Duggan a lot, not every time, but much much more than they were able to affect / tackle Stroud.
I, too, kinda would like to see TCU win the game but, IMO, no way.