The Hammers had to come from a goal behind to force a replay after failing to produce the kind of recent form that has seen them rise to 8th in the Premiership.
Speaking following the game the manager said, "We had so many chances that I was afraid we weren't going to score.
"We didn't deserve to lose and a draw may have been fair. A replay is not great news but we want to go through. It will be tougher but we want to go through."
The first 50 minutes was the worst we have played recently. It was not near our standards. After that we picked up a bit. You cannot afford not to play high levels.
"It's a good lesson for us. Three months ago we would have lost that game so I am pleased because the players showed we did not want to lose."