Hm. I would have to say this is a close one.
Starkiller proved to be a match for the Emperor, and while he is fighting the Emperor, Dooku may be able to get in a stab like with krayt. But Dooku is basically not comparable to Starkiller and Emperor's force prowess, so I'm not sure how much help he can be.
Originally posted by Lightsnake
Actually the databank states Starkiller was no match for him, to be fair
Well in the book, it seemed that Starkiller pretty much beat Vader and Emperor both, just that he turned around and the Emperor zapped his friend. If the stormtroopers hadn't arrived, I would think that the outcome would have been very different. The rebels wouldn't just have stood there, Kota and the rest would engage Vader or shoot at the emperor also.
But if thats what it says, then thats what it says. I can't argue against the databank. lol
In that case, the Emperor kills Starkiller with difficulty, and destroys Dooku.