I watched parts of the Murray/Verdasco match, and the ending was interesting. Verdasco was up two sets to one and serving for the match at 5-4 in the fourth. He is known to be a bit of a choker, and you could certainly see it at this stage.
On the first point he had a short sitter forehand, his specialty, and he flagged it long. As the game progressed he sprinkled in two double faults (the only ones he hit all set). I was getting nervous just watching him.
But there was another dynamic at work. And it was that Verdasco wasn't so nervous when he got down. This is typical of most players. They are most likely to get nervous when they are up and have a chance to win. But when they are down, the nerves go away. Now the danger is that the nerves will be replaced by discouragement. But if they aren't, the players are liable to play well when they are down. Verdasco did.
The last game see-sawed back and forth a number of times, with Verdasco playing good points when down break point and bad ones at deuce or when he was up. But now the final dynamic came into play. Here, even if a player has been choking trying to close out a match, the longer the game goes on the more the nerves will tend to dissipate. And they finally did for Verdasco. Murray made a mistake or two, Verdasco hit in a couple of good serves, and it was over.
The lesson to take from this is that if you get nervous trying to close a game, set, or match and fall behind, remain hopeful. If you can hang in for awhile and give yourself more opportunities, you are likely to eventually come through.