For the achievement you will need to score a smash shot to win the match. Generally the match ends on the 11th point unless the game was within 1 at the end (to win you must be up by 2).
I would advise not rushing through the match. Instead try to set up the opportunity for the smash shot on every point until you are confident enough to strike.Disclaimer:
This guide has specific movements that worked for me personally. I realize that there are people of may different shapes/sizes and it's possible that the specific motions won't work for everyone. I actually think they will, but if not I would advise trying out different types of swings to find something that consistently works for you. For the record I'm pretty average. Male, 5'9" with a average build.Setup:
To even attempt a smash shot the enemy will have to set you up. This occurs when the enemy returns the ball and it goes a little higher than normal and time slows down.
Your goal is on the final point of the match to keep the enemy alive long enough that this happens (seems random). You would think that hitting a slow return in the general direction of your opponent would allow them to return most often. Not so. It would seem that this makes your opponent prone to error. Instead stand still and attempt a slice shot across your body and slightly above your waist. So if you are right handed use your right hand to back hand from left to right. Do this at a mid level speed. If the ball is returned far too your right you may want to reach out and do a lazy forehand.Smash Shot:
To me once I got the opportunity for the shot it wasn't obvious how to actually preform a Smash Shot. This is what worked for me. When the slow-mo sequence begins move your entire body ether left or right so you are positioned directly behind the oncoming ball. Now remember the strategy I described in the last section to keep the opponent alive? Well we are gonna do the same arm motion, but this time do so violently as you lunge forward. If successful the word smash should appear on your screen.
Side Note: Do this no matter how far right the opponents set up shot is. You would think your strong swing to the right would cause you to miss wide right, but no. This never happened to me. The only shot that wasn't perfect to the right corner hit the net and the opponent missed it anyway.What if the Opponent Returns the Shot?
Any smash shot the enemy was able to return to me was another slow-mo setup. Just be prepared for the return by stepping back from your initial lunge and performing the same strategy again. Usually this will not happen more than twice in a row.