Remeber in the game you can beat Serra ketto in a minute without losing health(i can so Dooku probably can too)That leave's Shaak Ti Adi Gallia and Aayla Secura.If he could disable one of them by using force grasp or something it would be two on one,as he can handle Obi Wan and Anakin he can probably do the same with two weaker Jedi.If he would kill one of them,the one who was disabled before come's back in the fight he can do the same thing that will leave one Jedi.And that would probably Adi gallia.Now he's free to use force lightning if he feels so.
I still Dooku is going to lose... You have to remember that he is facing four Jedi here, that might not work well together but could at least try. By ROTS Obi and Anakin are a perfect team and still get their asses kickd I realise that, so Dooku is great. But could he block four lightsabers coming at him? Jump away use the force at all four of them when they are using it against him? I don't know...