Ki-Adi approaches and tries to force pull his lightsaber from the ground where he'd dropped it.
Grievous steps on it and then, amazing Ki-Adi, lifts it with his claw like foot and is now facing Ki-Adi armed with three lightsabers!
Ki-Adi takes a moment and then in a brilliant move, force pulls a saber from Grievous' middle section where he has at least four clipped. They face each other, Grievous balancing on one leg, his three sabers bouncing as he shifts his weight, Ki-Adi, poised in high combat stance.
Grievous leaps toward the Jedi, three light sabers drawn back to strike. Ki-Adi stands his ground....
This is when the first Clone Wars cartoon series ended.
Grievous was even more of a worthy villian in Clone Wars season II.
In the last episode, he has killed more Jedi and Clone Troopers and has kidnapped Palpatine. As he boards his shuttle, Mace Windu arrives and Grievous turns, expanding his four arms with light sabers in a battle stance similar to the inital stance he takes against Obi in ROTS. Mace leans forward, his hand toward Grievous and GG's chest structure caves in...leaving GG on his knees coughing and hacking...
The ramp of his shuttle closes and the ship escapes...
and that is why he is a stunted, hacking, coughing mess in ROTS.
I don't know how much input the creators of Clone Wars had in GG's performance but I know Lucas changed his mind before he edited the movie that Grievous was not really an unstoppable war machine, but a coward who would only fight when the odds were in his favor.