Boro more than held their own against their Barclays Premier League guests, and went close to snatching a famous win through Joel Byrom's fizzing effort, which just cleared the crossbar in the second half.
And Smith, who has only been in his new job for four weeks, was delighted by the performances of his players after they secured a fifth-round replay and a potential tie with Bolton in the last eight.
"I honestly thought we were capable here of being in the hat for the last eight," he said.
"Our players were terrific. Being involved in the FA Cup, with all its history is wonderful.
"There was a real intensity and tenacity. It's a wonderful competition and I am really pleased we are still in it."
