Are you serious?
Hmm lets see Yoda put Dooku on the defensive in just thirty seconds.
Dooku schooled Obi Wan and Anakin in AOTC and could have done so in ROTS.
Mace is apparantly as good as Dooku, but more importantly took out Sidious in a lightsaber fight, something Yoda said Obi Wan could never ever do. Yoda and Mace are in a league of their own.
Hmm, lets see...
A.
Mace vs. Obi-Wan = Obi-Wan puts a convincing fight and tries a trick or to but none of his tricks work work so he gets screwed.
Yoda vs. Anakin = Anakin concentrates as hard as he can and tries his very best but Yoda just twirles around a few times, breaks Anakin's defenses and kills him.
OR
B.
Mace vs. Anakin = Because of how much Anakin dislikes Mace he uses the Dark Side which akes him nearly strong enough to beat Mace but then he makes a huge mistake and gets killed. Or maybe Mace just slices off his legs and an arm, gets Anakin's lightsaber, then some lava comes... 🙂
Obi-Wan vs. Yoda = Obi-Wan tries a few tricks (as he did with Mace) but Yoda uses the tricks to his advantage and kills Obi-Wan.
So, as you see, Yoda and Mace'd win, no doubt about it. But I don't believe either of them could beat both Obi and Ani at the same time.