In Tennis Online, you’re about to have a tennis experience that is out of this world! Space aliens have come to earth. They’re challenging you to a match that will determine the fate of the planet! To save our world, you'll have to win your match against aliens. If you lose, the whole Earth will be incinerated! Use your arrow keys to move around the court, and hit the space key the right moment to swing your racket. At the start of each match, you get to choose the difficulty level and see your enemy's statistics.