Novak Djokovic or Andy Murray?

What are the scenarios as to who will end up number one at the end of the world? According to official website of ATP Tour there are several different ways both players can end up No.1. Murray will be No.1. if he wins the tournament. Novak has to win two of his three group-stage matches and win the title. Perhaps this will be one of the most stressful situations for Murray after his first time in Wimbledon final. Stay tuned for ATP Final Results throughout the week.