What do you think is the toughest thing to accomplish in sports when it comes to big, game winning moments?
I think I have to give my nod to the winning goalie in OT hockey. It's the only one that requires absolute perfection to win, especially when so many things are out of your control. And there is no second chance, your team can't make a comeback after a slight mistake.
Plus, it can last for 10 seconds or 4+ periods, so you have to be both 100% focused and in the moment, but have enough stamina to go as long as necessary.