"To be honest it was a surprise to be playing. But this was a big, big game and I've obviously proved to Rafa that I can play in them," said the England striker.
"The manager has played me in a massive game and I've got to take confidence from that.
"At the minute, it's not about me being unhappy or whatever. I have to pull together and be part of a team that has a chance of getting to the Champions League Final.
"The week ended fantastically for me. Everyone knows I haven't started nearly enough as I would have liked.
"But I've played in the last two now and hopefully I've done enough to continue in that role."