A singles player without a plan is a player in trouble.
Playing a lefty presents special problems. The vast majority of players are stronger and more versatile on their forehand side. The lefty is no exception; so adjust your shots to avoid his left side and attack his right side. Since this is exactly the opposite plan you should use against a righty (who represent 90 percent of all your opponents) you, not your lefty opponent, must reverse your game plan.
Also, lefty spin certainly breaks in the opposite direction. Again, you must adjust, not your lefty opponent.
Your lefty opponent plays right-handers most of the time.
Recognize left-handedness in the warm-up; don’t be the unfortunate player who loses a set before he discovers his oversight; I’ve done that; never again!
Play your game but reverse it and you’ll be doing the right thing.
Relish the thought that the sinister lefty will occassionally crash into another lefty.