I wish we could find out what his resting heart rate was versus his heart rate while up at the plate in a situation like that. He's so relaxed at the plate that he actually almost looks bored.
When it's all said and done, there will be plenty of players who will have had better numbers than David Ortiz, but I really think he's in a league of his own when it comes to clutch performances.
Billy Bean, the Oakland A's GM, claims that there's no such thing as being "clutch". I would challenge him to explain the performances of David Ortiz over the last few years.