I think Dooku was the only one who had Obi-Wan's number because Dooku basically had everyone's number. He certainly had no real problem with Yoda. (I haven't watched all of Clone Wars yet so maybe that's not true there but do me a favor and don't spoil it for me. :) ) Dooku was considered one of the true masters of the art, a former instructor of lightsaber technique with 50+ years of experience. Obi-Wan was a Jedi but still pretty green, so no big surprise that Dooku handled him.
IMO Dooku only lost to Anakin because of Sidious's scheming.