Victory for Nigel Worthington's side could put Northern Ireland top of World Cup Qualifying Group 3 with one match remaining.
Speaking to FIFA.com, Clingan said:"This is probably the biggest game I have been involved in, given what is at stake. To get to the World Cup would be unreal. It is what dreams are made of. But we all know it is going to be a hard shift against Slovakia.
"It would be great to beat them and get our own back. "There is good camaraderie in the camp and the confidence is growing. "There is a lot of belief in the squad and to take four points off Poland is something we would have accepted at the beginning of the campaign.
"Teams can also be a bit intimated when they come to Windsor Park. The fans get right behind us and the players really appreciate that. It should be another special night. Hopefully we can put a good performance in and get the right result."