Steve Cotterill issued an apology to Erik Huseklepp after a disappointing full debut from Pompey’s new boy.
The Norwegian international was given the Blues start fans had been clamouring for against Cardiff.
Asked to play in a striking role alongside Dave Kitson, it was a tough baptism for the 26-year-old.
He was switched to the left wing after the interval before being substituted for Benjani Mwaruwari in the 61st minute.
It was a low-key display from Huseklepp after the mouth-watering cameo at Bristol City last weekend.
And Cotterill, who saw his side claim a 1-1 draw, conceded he was responsible.
He said: ‘Erik was average.
‘He’s only a young boy, he has come over here and everything is new for him.
‘He would have been part of all the other players I have over-trained this week.
‘Not only does he get my apologies, they all do.
‘It was a bit of a lethargic performance really, we weren’t quite at it – we weren’t quite at full belt.
‘That was my fault really, I have over-trained them this week and I have to take responsibility for that.
‘I think we would have been a yard sharper. Hands up, I let the players down this week.
‘It wasn’t a bad performance at all – no problem with that – we just didn’t quite have that zip in us when we needed it.
‘We’ve had so many players in we worked so hard and spent a lot of time on the training ground. I think unfortunately I left a little bit of their legs on the training ground.
‘There were a couple of balls spinning around and they get a foot to them and clear them off the line as opposed to us getting a foot to them and knocking them into the back of the net.
‘Two goal-line clearances we were close enough but if we were a yard sharper we would have toe-poked it over the line.
‘However, we didn’t quite have that sharpness in us and that is my fault.’
Kanu grabbed a point for the Blues in the 80th minute.
He had been on the pitch for only three minutes after coming on to replace Luke Varney.
Yet it was a substitution which ultimately earned Cotterill’s men a 1-1 draw.
He said: ‘We changed our formation a little bit when we made our substitutions.
‘Sometimes that works, sometimes it doesn’t. Somewhere along the line I needed to redeem myself a little bit.
‘It was scant consolation for me after my mistake but I managed to do something to change it.’