Simon Ireland was sent-off for City after an elbow on Young-Pyo Lee, while Pascal Chimbonda appeared to be offside when he nudged in the game's first goal.
Even if it was not a punch that would have troubled City fan Ricky Hatton, the full-back also appeared to use his arm to divert Dimitar Berbatov's flick on the stroke of half-time.
"It's nothing to discuss, the referees in this country are honest and always try to do their best," Eriksson said.
Rolando Bianchi was brought on just before hour mark and made an instant impact, thudding home a header from Martin Petrov's corner.
City looked like seizing the initiative until Ireland's tackle.
"It's a little bit late if he wants to prove a point to me today - I will not be the next man for the job," said Eriksson.
"He is one of the better strikers but the situation, which was a long time ago, was that he didn't play many games during the year. That was the reason why I took one who almost never played. I gambled. That was the reason. Of course he is a good player."