The manager, who saw full-back Martin Olsson sent off at St James' Park, believes that there was a foul in the build-up to Newcastle's third goal.
"I thought the overall turning point was the decision for their third goal because for us hitting the top of the bar and getting an equaliser it was tough, because we feel it was a foul on Scott Dann as he was about to clear the ball off the line," he told reporters after the match.
"I think it was a good back-post header but I think Scott’s just about to head it off the line and we feel that Leon [Best] has come over the top of Dann and Scott’s been pushed into Paul Robinson.
"It’s not only we feel that it’s a foul but we also pick up a card for Martin Olsson protesting against that goal. I think you can always tell by the reaction of the players, the Newcastle players all looked at the linesman expecting to see a flag go up but it never came."
Blackburn currently sit 18th in the table, having collected four points from their opening six matches.