I'm sure my opponents were having their own internal roller coaster. i can only tell my side of the story
That strong guy i beat also played the rookie tournament the day before. He played the morning draw in a competitive 39- category where he probably played only (many?) intense matches and perhaps had a good tournament and many emotions ? The lunch break maybe broke his focus and momentum, in the afternoon draw he had before me two even easier matches in his group, and already had switched mode to play "easy" to give him a bit more rest. He had beaten me easily before, but also lost two matches to my 2 other French teammates in the past (but they are much stronger than me) and didn't want to feel the "shame" of losing to old gaijin again, in front of his gf ???
you can often see a pro making a wonderful match in the morning or early afternoon against a much stronger player, get a big win, and then the next day or even in the evening lose it to a guy of his level.
As for tactics, all the players mentioned in the afternoon draw were familiar to each other as we've been playing against each other or watching the other play in tournaments or practice. so I knew what tactics i would use, i know who is a good matchup or not, which is as important or more perhaps than the supposed skill difference. but yes, if i can give an advice to my opponents: don't play the same next time; vary more your serve placement and make you serves more unpredictable because thats what i have trouble with, not so much serve quality. too bad for them they couldn't figure it out.
As for mentality, I definitely was in the zone. It sometimes happen. not easy to get in, i use a lot of shouting and only positive self-taking and (Monster) energy drink to help me. friends watching me play usually helps a lot too. could write a lot about it.
As for luck in TT, my strong belief is it always favor the player who's taking the more initiative and putting more quality in his ball. You hit the net often because your arc is low and it goes on the good side of the table because you put good spin. Its part of the game and a good sign that you're winning on quality if luck is on your side more often.
Another factor is my brand new very fast and low topspin serve (from both FH and BH) its totally obvious that I'm going to do it, but there is a lot of quality in it and its very unusual and im able to do this serve from different positions and aim different part of the tables and decide placement at last moment; nobody else does it. I've been practicing it a lot recently and it did work very well as people are not used to it and i can play behind it usually with an early advantage. so maybe this new skill which is not 100% reliable yet - and also depends on how fast the tables are - starts to be a quantifiable upgrade.
I'm giving me a good slap in the back for having the courage to use it in abundance already in matches even (or especially !) in tight moments whereas some serves that i've been practicing much more for years (pendulum) i still can't rely on it in matches.
its so unusual i could even make a YT tutorial on it, never seen any. i got the idea of doing it after watching another guy doing this kind of serve (but a different technique) to come back and win a match from a desperate situation