The sides will meet again at Hamilton Academical's New Douglas Park on Monday night after Bilel Mohsni's disputed 78th-minute equaliser earned Ally McCoist's team a William Hill Scottish Cup quarter-final replay, Donnelly having put the Coatbridge team ahead after 14 minutes. Conventional wisdom suggests an opportunity has passed Rovers by but Donnelly refuses to believe the tie is over bar the shouting.
The midfielder, who works as a gas fitter, said: "I thought we could beat Rangers at Ibrox and my feeling won't change for the replay - we'll just need to prove we can do it.
"Rangers are a good side. Anyone who says they are not is talking nonsense as they are a cracking team who would do really well in the Premiership if that's where they were playing.
"But we'll just need to go again and see what we can do. Taking them to a replay was a cracking result for us and for the fans it's amazing. The manager has been really calm about it.
"Everyone has been talking about how disciplined we were against Motherwell [whom Rovers knocked out in the fourth round] and we felt we could really do something again.
"We bought into it and we knew that if everyone stuck to their jobs we'd have a chance."
The draw at Ibrox and subsequent replay will earn Rovers, who came close to beating Rangers for the first time since 1932, a significant financial windfall.
However, Donnelly admitted he and his team-mates were disappointed they had not been able to settle the tie at the first attempt.
"I'm still thinking about it now," he said. "The fans enjoyed the game but the players are devastated. Not many teams will come to Ibrox and do as well as we died. I thought the draw was the least we deserved and the result does feel like a defeat."
The part-timer took his early goal superbly, volleying home after Rangers failed to clear a corner, but its timing meant Rovers had to spend most of the game grimly defending it.
Donnelly agrees they might have left Ibrox with a semi-final place against Dundee United in the bag had they netted at the same time as they did against Motherwell when a Gary Phillips strike in injury time earned James ward's team a famous win.
Donnelly said: "I was delighted to score but it was a pity we couldn't hang on for the win.
"It was great to score so late against Motherwell earlier in the cup as we didn't have long to hold on. We scored early against Rangers and I knew we'd have to hang on and work hard, but to be honest any goal at Ibrox is good.
"At the time, I was just thinking that I needed to get on to the ball and make sure I scored. Only when I was running away did I think it was a comfortable finish."