Clingan, 25, hopes to take another step towards that exciting possibility on Wednesday at Windsor Park.
Victory for Northern Ireland in the qualifier against Slovakia would see them overtake the Group Three leaders with only one match with the Czech Republic remaining.
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."
Northern Ireland are now unbeaten in five competitive matches and secured a point against Poland in Chorzow at the weekend.
Nigel Worthington's side have made up ground after a poor start, which saw them lose 2-1 to Slovakia in the opening game.
Clingan said: "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."
Meanwhile striker Billy Kee has been backed to take promotion to the senior squad in his stride.
That's the verdict of under-21 manager Steve Beaglehole, who is also coach at Kee's parent club Leicester.
The 18-year-old has been loaned out to League Two side Accrington to gain experience after suffering a knee injury last season that curtailed his progress.
Kee was due to play for the under-21s against Iceland tomorrow but instead has a date in Belfast as Kyle Lafferty may be sidelined with a knee injury.
Beaglehole said: "It is quiet unbelievable what is happening to Billy. It is the stuff you read about in comics - real Roy of the Rovers.
"A lot of the time you wonder if the fear factor will kick in when you promote a player.
"But Billy will be able to cope, no problem. If he was required in the game, it would not faze him."