BenLaw said:
Not sure why it was on a Monday. I would have thought a five set match starting around 5pm on a Sunday would make for a better atmosphere and match.
The final is on a Monday because the tennis calendar has been condensed since 2011. The Paris Masters ends on the first Sunday in November, forcing the ATP World Tour Finals to start and end on a Monday.
From next year, there'll be a week off between these events, with the World Tour Finals starting and ending on a Sunday. I agree that this works better. It'll probably make for more competitive tennis, too, since players will have a week to recharge.
Either way, it's perhaps unfair to ask players to fight through five sets at the end of the season, even though I'd prefer that as a spectator.