Smith headed Oldham's equaliser deep into stoppage time but was quick to pay tribute to the performance of his teammates.
"Credit to the team, it was an unbelievable performance from the keeper to the substitutes," BBC Sport quotes Smith as saying.
"We have been working on inswinging crosses all week. It was a tremendous cross and I managed to get my head on it. Of course we deserved a replay, especially for our second-half display.
"We left it to the death but they all count. It was up there and we gave hard work and endeavour from start to finish. We'll go to Everton for the replay full of confidence."
Oldham are struggling in League One and sit in 21st.