I firmly believe that the better or elite players at ANY level of play make thier own luck.
I have certainly made my own share of bad luck and whenever I look back, I can see it was not something unfortunate, but it was something correctable in tactics or execution of basics.
I find that I create my best chances in matches where I should expect to be the loser vs a top player in my division (or a strong player from a division higher) when I can avoid playing tight. I now understand that staying loose is a mentality that can be obtained, yet easy to lose during a match. If I enter a match looking only to compete and show that other player what I can do, without the pressure of trying to dominate or over-do anything, I find I do MUCH better and can perform in the clutch situations with much less error, better confidence, and play many more positive shots that lead to points won.
I try to tell myself... "Come on William, you are here to show him you deserve to be here and can COMPETE. Show him." I do NOT try to tell myself I HAVE to win htis match or point. That seems to lead to unproductive pressure or playing too tight.
It seems that in hte late stages of the match if everything is close, the winner is usually hte one who can still land their shot by avoiding the inevitable trap of playing too tense. Staying loose in body, as well as attitude is a real easy concept to advocate, but a whole heap more difficult to adhere to when the match is on the line. Those who manage these situations positively tend to make their own luck and deserve teh results, just as well as those who tighten up and lose also deserve the results.