Match stress, are you kidding. Do you mean the stress you felt when had butterflies in your tummy before competing? That is nothing! That is not stress of any significant amount. A match is a fun thing to shoot or at least it should be. Sure you may get a little jittery when you get there, but you have all the time in the world to calm yourself before you shoot, and to think about your technique as you are getting your gear ready and as you talk to the other shooters, the range personnel or your coach.
Of course if it is a tactical match, then all the jitters should go right down the toilet as soon as you hit the tactical course. The tiny bit of adrenaline that causes the jitters is immediately being directed to your running, or climbing, or crawling, scanning targets for hostiles and so forth, and of course you also had time to get yourself ready to shoot before the match time begins.
On the street in a real SHTF situation, there is no time to talk to the other shooters, or to the coach, or too adjust your equipment and slowly think about things. You had best be well trained, well equipped, alert, ready for action, and pretty much have some sort of a plan before the SH it comes off of that fan and winds up in your face. There is no second guessing, no coaching, no one saying to you 'aw too bad maybe next time', because it is a life and death scenario, and it is not a piece of paper at which you will be shooting. Your stress management under these circumstances may go right out the window, but you need only do one thing even if you are so scared you poop yourself. You have to fight to win.
Once you realize the SHTF the first thing that takes place on your part of which you may or may not be aware is a surge of adrenaline and I do mean a MEGA surge. Along with that surge you had best already be taking action - not to control the adrenaline that just pumped into your system but to control the situation. If the situation lasts for more than about a minute or two, you will feel that adrenaline, you may well start to get very jittery or even start shaking, you may get scared, you may realize that you have peed in your pants or crapped yourself because the pucker factor failed you. Whatever you do, if you have trained to take action, then you have an advantage over someone who is not trained. If you were trained to improvise all the better for you. In the great majority of shooting scenarios the shooter resorts to his or her training. Thus even if you are in a sheer panic and start to blubber like a baby, you may be able to take the appropriate action because you were trained to do so.
I know this for a fact because I have been there and done it in a hand to hand combat situation where a guy tried to take away my gun and shoot me with it. I almost started to cry I was so friggin scared because I thought he was going to do it to me. Yet no matter how scared I was, I got the advantage, kept my gun, and finally got the situation under control because I knew enough to keep up the fight. The important thing is not to give in to the fear, and do nothing - keep up the fight.
I have also heard of several cases when people have actually wet their pants or dirtied them but they just kept fighting. They later recalled a warm sensation during the fight, one or two even realized what had happened but kept up the fight. It is important to pay attention to the tactical situation not the inconsequential side effects.
Even people who have been shot several times have survived because they continued the fight. They knew they were shot too and were plenty scared and thought maybe they were going to die, but did not give in to it. They had the mindset to do so beforehand because that is how they were trained and how they conditioned themselves.
Know that when you are suddenly pulled out of your comfortable version of reality and thrown into a firefight or other fight for your life, you need to focus on one thing and one thing alone, defeating your opponent. You have to forget the hunger pangs you were feeling, forget you just found out your wife is screwing the mailman, forget your sore toe that you dropped a hammer on yesterday, forget the fear that just overwhelmed you, and remember how to fight to win even if you never paid attention to any of your instrcutors about tactics. Then when it is all over, you worry about whether or not you took a round or if you crapped in your pants. When your life is in the balance, even if the odds are in the other guy's favor, you should fight like a wildcat to survive. Don't give up. Train yourself to take action, plan to be a winner and to be a survivor. Don't wind up doing nothing except dying.
Match or Range stress indeed, is nothing at all compared to the real life stress of a fight for your life - you should prepare for the latter and forget about the former.