Lot of that is on Green too. They lost the lead with Green playing a key role:
1. Continually losing their hot 3 pt shooter Hayward on the perimeter.
2. A really bad lazy inbounds pass attempt to Duncan that was stolen and they scored. No excuse for that one either.
3. You expect an NBA player to be able to make layups, especially wide-open shots at the rim. This isn't an exception with Green; he really has a lay-up problem.
4. Everyone in the stadium and at home watching Mo Williams hold the ball knew he was going to try to win the game with a last second shot. Green laid way off because Mo was so far out past the arc, but he should have closed the gap at 5 seconds and harassed his dribble to make Williams worry and possibly change his option from shooting to passing.