"For me, it doesn't matter if it's from the side or the front. A kick against the head is always dangerous, because you could injure your opponent."

Rangers' feelings of injustice were heightened by the fact referee Nick Walsh had earlier sent off midfielder Thelo Aasgaard for a high tackle on Celtic right-back Anthony Ralston.

"I think you have always two sides," Rohl said. "The refs have their side and they're looking for the rules and we have our side and how we see something.

"It's a little bit more difficult with hand ball as there's so many rules with hand ball: is it this angle, is it that angle. But the tackle was difficult to understand. We got the red card, our opponent didn't."

Meanwhile, Rohl again praised his players for taking the tie to extra-time despite being reduced to 10 men.

"Even with the red card, we took it right to the end, but it was still not enough," he added.