Greivous: Back away I will deal with this scum myself.
Obi-Wan: Your move.
Greivous: I will stare down on your body like I did your master's
(Off screen) Obi-Wan: Maul?
Greivous : Ah, yes. Bright aren't you.
Obi-Wan raises his saber and the fight continues as normal until the clones arrive then their second exchange would go as such:
(Close up of Greivous' eyes) Greivous: You will die by my blade.
(Close up of Obi-Wan's eyes) Obi-Wan: I don't think so.
This is just an idea.