Stekelenburg got to the ball first and Lucio followed through, kicking him in the right temple. The Dutchman was stretchered off unconscious and kept in hospital overnight for observation, but only required two stitches.
"I saw the video replays," Lucio told Mediaset. "It all happened in a split second. The ball moved quickly on the wet turf, Stekelenburg came off his line rapidly.
"I didn't see him because I was looking at the ball. I thought I'd kicked the ball and was surprised by how quickly Stekelenburg came at me.
"During the half-time break I spoke to the Roma doctor and he reassured me on Stekelenburg's condition. Thank God, I heard today it was nothing serious either, so this calmed me.
"This morning I also spoke with Wesley Sneijder, who is in contact with him and said he's doing alright."