The Croatian striker scored the winner in Wednesday's replay against Wigan and he was on target again on Sunday as Bolton beat Fulham 1-0 to book a quarter-final trip to Birmingham.
Greater Manchester Police have confirmed that Klasnic will not face charges over the alleged rape of a teenage girl, following an investigation dating back to October. Coyle praised Klasnic for the manner in which he handled a difficult situation - and the way he has bounced back.
"We are delighted the news broke there would be no case to answer," Coyle said. "We knew from the outset he had done nothing wrong. Ivan was in a bad position because we couldn't really say anything because of the extent of what was involved.
"A lot of people look up to Ivan because of his fanbase in Croatia and Germany and the level he has always played at. It was horrible for him that they would have to read that, particularly when he was totally innocent.
"He has tried to deal with it with a smile on his face. He probably felt his family were hurt more than himself because he knew he had done nothing wrong. We are glad it is away and hopefully we can see the best of Ivan now in the run-in. Ivan is a natural goalscorer. There is still more to come from him."