Roman Pavlyuchenko was critical of his own performance on Saturday, stressing that his reaction to being substituted was a mark of frustration at himself and not at being substituted.
The Russian international headed straight to the changing room following his withdrawal against Manchester City after 75 minutes.
"During the game I had a couple of chances to score but I didn't take those chances so I was angry at myself when I came off the pitch, not at the decision to replace me," explained Roman.
"I know it was not my best performance but I blame myself for that and nobody else.
"I did not mean to cause offence with my actions and I apologise to my team-mates, the coaching staff and the supporters, who have treated me so well since I arrived.
"To get the opportunity to show my appreciation to the fans during the walk round with my team-mates at the end of the game was a special moment. They have been so welcoming and supportive towards me .
"It is now up to me to go away and work on sharpening up in front of goal."