Colin Kazim-Richards fired Rovers ahead just before the break and second-half goals from Scott Dann and Jordan Rhodes shattered County's hopes of reaching the fifth round.
Clough cast an envious glance at Blackburn's experienced line-up and accepted that his team were well beaten.
He said: "Blackburn were a bit too good for us although there was nothing in it until we paid for a bad mistake with their first goal just before the break.
"After that, their experience and physical strength shone through and our young lads found them hard to handle.
"Jordan Rhodes and Colin (Kazim) Richards are as big a handful as any attacking partnership at our level and it was also a tough task for our kids to come up against a player like Danny Murphy in midfield."