Tournament play reminds me that the majority of athletes, coaches, and fans believe in "clutch performance" - an athlete who rises to the occasion as the games get more important and the end of the game approaches. I tend not to. I don't rule it out. There may be players who can "take it to another level," or whatever other cliche you might like, but whenever someone tries to measure it, it seems elusive.
What I think is more common is "choking," playing less well under pressure. I think anxiety can be shown to reduce performance in many areas. Being a clutch player, then, might simply be holding to your usual level of ability when everyone around you is making mistakes. Which is certainly about the same thing, as a practical matter. It just doesn't make such a great movie. You will not rise to the occasion. You will revert to the level of your training.