Datafile
Foreword
Atari had a weakness in its catalog, and those were the sports titles. True, there were some, but they were facing a fierce competition, specially from Mattel’s Intellivision.
Having already cashed out the legendary Pong, finally it was decide to launch a title about two players hitting a ball using racquets, better known as tennis. In this situation, as part of its Realsports lineup. Probably the last one on being programmed (at least for a few years) and it’s notorious that lessons were learned from previous attempts, and not only from Atari.
Game
The game uses a vertical perspective of a very realistic tennis court, even if the lines which limit a valid serve are missing, and quite frankly rose and purple are not exactly the first colors blue and red are that you can expect at first on the virtual players and in the scoring system when it appears after winning either a point, or a set. The match of a one-player only game is to win one set two sets and the AI can be a really hard rival, specially if the point goes on and on, like a match between Nadal vs Federer, sorry, Borg vs McEnroe Connors vs Lendl which is closer to the time of this videogame release. Even the scoring system of winning by two points of difference is respected (until deuce). Two-player games are to win two sets.

OK, enough with the joke, the last paragraph is copied/adapted from the entry about the game Tennis from Activision; and that is because at the time, this game was very criticized for being a copy from the Activision one because of the similarities between the graphics of field and players. IMO is not that way, the distribution of the field is similar to other tennis games of the time. And with the virtual players you did not have too much room to improve.
At first, the screen title, few Atari 2600 games at the time had one, and this one was animated. After that, you can put a name (up until 8 characters) to appear at the scoreboard. In 1983 that was a big deal. At the time of play, the control was exactly the same as the Activision one, with the difference that with the difficult switches you can make the button able to make a swing to hit the ball. There are two speeds to choose, and two players can compete, which is the most recommended way to play.
In one players matches, I consider the AI easier to beat than in the Activision game. I highly suggest to use slow speed and auto swings if you are beginners at the game; otherwise, use fast speed and do the swings with the button for a nice challenge.
Other Platforms
Atari 8Bit

It was very common that almost every videogame made by Atari at mid 80s had ports for every platform sold by Atari. The version for 8bit computers has notable improvements in graphics, even in difficulty, but adds a method to return the shoots… well, it had points for trying new things.
The idea of moving the virtual player with the joystick still applies. But the button has another use, the swings are automated, only that just before the swing starts, you can press the button and with the joystick indicate where to aim the shoot. That suddenly stops the player you are controlling, and really there is no major difference to where the ball goes, although it’s possible to make very sharp shoots with enough practice. If no direction is specified, the ball goes to the center of the court.
Just like the Atari 2600 version, it’s possible to put your name in the scoreboard. The difficulty is still the same, but the new feature is the doubles mode, where two human players can compete (or you can play alone), where every human player has a “partner” in the court which become very competent. There are two skill levels, using the easier one is recommended.
As a funny note, the game only appeared as Realsports Tennis, in catalogs. In the instruction manual, along as the screen tigle, the game was called Tennis.
Atari 5200

As usual, the game is practically the same as the 8bit version. The main difference is in the use of the control. Instead of suddenly stopping the player, pressing the button and using the joystick, you use the keypad keys of the control to aim the shoot. When the instruction manuals gives suggestions on how you must get the control for using it, we can see it was not exactly ergonomic.
But many years later, thanks to emulation and the ability to program one of the two sticks of any standard gamepad, it can be very playable and useful. The idea of aiming the shoot was good, at first you can think there is a problem was executing it at the time because of the controversial controller, but according to some users of the game at the time, there was not a big problem at using it.
This game was compatible with the huge trackball controller of the console. I suppose this particular game was quite fun to play using that kind of controller. Also, according to twitter user AtariSpot even if the manual did not mention it, four players can participate in the game, so I can imagine playing with four trackballs would be insanely fun.
Epilogue
I had oportunity to play this game before the Activision one, and it became quite popular between my circle of friends, specially for the feature of putting your name on the scoreboard.
The 1-player matches could be a bit boring, because it was a bit easy to win. I did not have enough patience for a full match of winning two of three sets, normally I played only for a set, not caring how finished the match.
Generally, a nice tennis videogame, easy to learn and not too hard to master.
References
Sport Icon designed by Smashicons of FlatIcon licensed by CC 3.0 BY.
Console Icons taken from Retroarch.
Trackball controller image taken from Atari Age.