"Graham Poll is the best referee in the country but he didn't help our cause in not sending the player off," said Francis.
"He had already been booked and I couldn't see whether he was the last defender or not. But he clearly brought Andrew Johnson down and I would have thought that was a yellow card.
"With 15 minutes to go, it would have made a lot of difference to us to be playing against 10 men in the final stages."