Complex sentence: The premiership is usually decided by a single match; however, as the first Grand Final ended in a draw, a Grand Final replay was played the following week and was won by Collingwood.
Split into simpler sentences: The premiership is usually decided by a single match. However, as the first Grand Final ended in a draw, a second match--known as the Grand Final replay--was played a week later and was won by Collingwood.