If it connects to a Sega console, then it's going to have the individual control signals on different pins (like in your link). You said the controller was a serial connection which would make it very difficult to use as is. If it's really usable on an old console, that means it's not really a serial controller. Anyway, if that pinout is correct, then you can easily use this thing with a USB controller hack or probably with a parallel port hack (if your laptop has a parallel port).
BUT, you need to figure out what's coming out of those pins first. You can do that by connecting a multimeter to the ground pin and to each control pin. When you press a button on the gamepad, one of the lines should go to ground. Finding ground is really the hard part though. Try using that pinout and you will know pretty quickly if it's a Sega controller or not.