The Saibaman is a species. You fight one of them that represents the whole species. They are working for Nappa, which will be your next battle. Although the Saibaman's Ki number may be intimidating, it seems to be a break from the earlier battles. This should be an easy battle. Fight the Saibaman for the higher HP and Ki, and you'll be ready for the next battle.
A big break before the final two battles, you might notice that this battle doesn't have as much tension surrounding it. It's probably not the easiest in the game, so you shouldn't completely let your guard down, but it is an easier way to score some major HP and Ki points for the later battles. Do your best on this one instead of taking it lightly, as you'll be needing that HP and Ki later on.
The Saibaman will attack first, so defend and then move on to attacking. After the Saibaman attacks, you'll end up being right in front of him. Try using a combo by linking your attacks together. This gives your opponent less time to recover from the first attack, which gives you a better chance of landing the attacks. You should have at least 85 Ki by now. Now you can use more Ki attacks. Practice your strategies against the Saibaman, and you can use the successful ones on Nappa. Also try to keep your HP up for most of the battles, as you'll probably get more credits for your next battle. The next battle will be a hard one, so consider this a training session. Also remember that you can power up, but this wastes one of your moves. Use it only if necessary, and if you do, use it as your starting move instead of using it in the middle. This way, you can have your Ki saved for the attacks you're about to land.
Defending in this battle is the same as any other battle. You'll have a lot to defend from, since he has the same number of moves as you. Most of the time, he'll chain together attacks with combos. This wastes his Ki, but this also means more for you to defend. He'll usually use attacks that don't involve Ki besides that. Either dodge or block until it's your turn to attack. In comparison to attacking, defending is probably a bit more challenging in this battle.