Dooku because he was trained by both Yoda and Palpatine, two of the most skilled duelists in the galaxy, and the best of their kind.

Lore wise, Kenobi. A master of Soresu can outlast all opponents

Dooku was literally one of the greatest duelists in the Jedi order. His fighting style was made for it.

Edit: An excerpt from his Wook page;

“Dooku was a highly skillful lightsaber duelist even in his old age. During his time as a Jedi, he was known as one of the Order's finest swordsmen; it was said that Yoda was his only superior and Mace Windu was his only equal.“

On this list, Dooku, followed by Mace

Dooku has been stated to be one of the best lightsaber duelist’s in the history of the Jedi order. His lightsaber form of makashi is perfectly designed for blade to blade combat, and he was said to be the best user of the form in the history of the Jedi as well. During his prime it was said that only Yoda was his superior in an even fight. On top of that he has decades of experience to draw on. He is my favorite Star Wars character and I would want him as my master if I was a Jedi or a Sith.

I believe that Obi-Wan is a better Duelist.

I say this because he was skilled enough to take on Darth Maul, Dooku, Grievous and Anakin (which all of them were tough)

Plus he had good skill with a Lightsaber and taught Anakin everything he knew.

Also Obi-Wan had a cool Lightsaber battles

Dooku was really underrated imo, he was so strong yet so slept on