Although Super Tennis (Great Tennis in Japan) was one of the earliest Master System games (from 1986), and although it was originally released on a card and is only 32 Kb ... it still sucks. Actually I think this is one of the worst tennis games I've ever played. At first sight, I guess you could say it has some kind of charm to it (after all, many people probably had it, because it was a cheap and accessible game, and probably feel somewhat nostalgic about it), but when you start playing it, you realize what an awful tennis simulator it is.
Just being able to hit the ball is extremely difficult (most of the time it hits your body instead), and if you do manage to hit it, you have no way of controlling where you want it to land. Unless you change the settings in the beginning of the game, it is also an extremely slow game. It takes forever for the ball to move across the tennis court, and it is also difficult to anticipate where it is going to land. Actually you move much faster than the ball (!), and if you miss it, you can run back and try again a few more times! Not so realistic ...
It gets somewhat better if you speed the game up in the settings page, but some parts of it is still slow. Like serving. You press button 1 - nothing happens for two seconds - then the guy you're controlling throws the ball in the air, and it probably uses five seconds on it's way up, and five seconds on it's way down again. So even though you have set speed to maximum, serving is still extremely slow and tedious. And as you have no way of controlling where the ball will land, sometimes when you serve, the ball ends up far away from the part of the field it's supposed to go. A second time with this and you have a double fault, even though you have done nothing wrong. To summarize: the controls in the this game are awful!
I'm not too impressed with the graphics either. If this was a Commodore 64 game it would probably be OK, but I expect much better from a Master System game. After all, "The Ninja" was released the same year as Super Tennis, and has much better graphics. And even though Super Tennis is only 32 Kb, it's the same screen you see all the time (the tennis court), so you would think they could have squeezed some more into it. Some of the sound effects are cheesy too.
Super Tennis/Great Tennis is neither super, nor great, and it would take a few more years (Wimbledon/1992) before a decent tennis game was released for the Master System. That you in 2 player mode is only able to play co-op against the computer and not against each other, sums it all up.