So, McIlroy and Spaun will do battle over the final three holes of the course - the 16th, 17th, and 18th.

The format is simple. The man who takes the least shots over the three holes will be declared the winner. However, if the players are level after the last, it becomes sudden death.

That means the two will head back to the 16th and whoever wins the hole will take the silverware. If they still can't be separated, the sudden death format will stay in play for the 17th and the 18th holes - and the two rivals may even have to head back to the 16th if needs be. 

So it could be all over in a few minutes.....or we might be left hanging on for hours.