I lost this game, but it could have gone either way (I've actually made a post before about how I could have one that last point).
If you want to beat a player that is better than you, then you first must have something that you can
threaten the opponent with, something you can rely on to win points from the opponent.
If you do not have a skill of some kind that can give them trouble, there is no way for you to win ( unless you have godly luck, which if you do, go play the lottery).
There are many ways you can threaten your opponent. However, if your opponent is better than you, then chances are, the quality of the shots you have right now might be subpar. Your usual shots that win points, might not win points against them. So one of the first obstacles you face when you play against someone better than you is
SHOT QUALITY
*********
Consider this scenario:
You play in an event suitable for your rating, but then you see that you have to play really good, super-underrated player and you know you will lose if you play normally. What do you do?
A lot of the time, if all of your shots aren't good enough, you are going to have to take risks to do so. Take risks to hit harder. Take risks in service and service return. etc. Hopefully you will make enough points to turn the game around. Otherwise, your opponent will simply stomp their way past your game.
However, if you do have strengths that can threaten your opponent: first you must know your own strengths. second, you have to force your opponent to play into them, and then you can use them.
Even better, if you can find and consistently capitalize on a weakness that your opponent has, you have a very good chance at winning.
If not, then just accept the loss. There is no shame in losing to someone that is a lot better than you as long as you try.
***************
Consider a different scenario:
There's two days left before the tournament and you signed up for higher rated events. What do you do?
The best thing to do (in my opinion) is to first practice and specialize in certain shots you can use on better opponents. Don't practice routines that rely on your opponent messing up. Specialize in it and practice it until the quality of those shots is higher than your own level. There are many ways you can improve the quality of your shot, mainly speed, spin, depth, and placement. Other ways can be deception, height, and timing.
I see a lot of the time that players like to specialize in a single shot, because they like to do that one shot. This isn't enough against better players, since a rally usually doesn't consist of that one shot. Not only that, your opponent will catch on really quickly and find a way around it. Ideally, you specialize in
a routine, a set of shots.
For example, a simple routine can be:
1. wide side-topspin barely half-long serve, and hopefully bait your opponent to loop cross court
2. counter-loop down the line (hopefully win the point)
It's even better if you have multiple routines.
Another important thing: your service quality has to be good. If not, you will lose the initiative right away. Make sure you have a safe short underspin serve to discourage better players from attacking right away.
Long story short: what you just read is actually "Get good"
Oh yeah, and use the tips in the first part as well.
***************
Another obstacle that you will face is consistency.
Since your opponent is better than you, always assume that they will get the ball back. Never get overconfident. However, don't play too shyly either. Play confidently. Play smart. Don't give up, because upsets do happen from time to time.
Your opponent will probably have better shot quality than you do, so ideally, you prevent that from happening while minimizing your own mistakes. This can be tough to do, but if you can pull it off, that's great.
By the way, the easiest way to prevent your opponent from making good quality shots and break down their consistency is to improve the quality of your own shots.
*********
Dirty tactics:
This is situational, but another thing you can do is hide your own weakness. If you aren't good at a shot and you miss it: you can pretend you got unlucky. This is temporary though, and if your opponent catches on, you're screwed.
HOWEVER: you can handle this in a different way. When you are forced to do the shot that you are bad at: pretend you are the world champion and hit it like the world champ. IF YOU GET LUCKY AND MAKE IT, you can pretend that you were always a master at that and your opponent might not ever make you do that again.
I did this at the start of the match pictured above. I am not too great at attacking fast topspin serves, but Ahmed served that at the start. I looped it as hard as I could right away, and won the point. He never served that again. He stuck to other serves, which suited my game better. He simply assumed that lefty-penhold me had a good enough forehand to handle serves like that.
************
I always have certain shots that can threaten better opponents. One of the first things that I do in a match against somebody that is good is serve fast heavy sideunderspin as far as I can to the backhand. It doesn't even matter if they return it or not (I get the point most of the time actually). The whole point of that serve is to let my opponent know that this threat exists, making my opponent think twice about moving over to backhand flip my short serves. I like to remind my opponent of this from time to time throughout the match.
Another thing that I can threaten my opponents with it my loop against underspin. I know that this is my strength and I know it give even very good players trouble. I set up my short underspin serves and I play from there. A lot of my routines revolved around this safe serve that I had, and so I am able to use my routines against players of all levels.