People really do seem to underestimate Obi-Wan's performance against the good Count in Revenge of the Sith.
'He leaned into a thrust at Kenobi's gut that the Jedi Master deflected with a rising parry, bringing them chest-to-chest, blades flaring, locked together a handbreadth from each other's throats. "Your moves are too slow, Kenobi. Too predictable. You'll have to do better."
Kenobi's response to this friendly word was to regard him with a twinkle of gentle amusement in his eye.
"Very well, then," the Jedi said, and shot straight upward over Dooku's head so fast it seemed he'd vanished.
And in the space where Kenobi's chest had been was now only the blue lightning of Skywalker's blade driving straight for Dooku's heart.'
-Revenge of the Sith
'But by the time his boots touched down Kenobi was there to meet him, blade weaving through a defensive velocity so bewilderingly fast that Dooku dared not even try a strike; he threw a feint toward Kenobi's face, then dropped and spun in a reverse ankle-sweep-But not only did Kenobi easily overleap this attack, Dooku nearly lost his own foot to a slash from Skywalker who had again come out of nowhere and now carved through the table so that it collapsed under Dooku's weight and dumped the Sith Lord to the floor.
This was not in the plan.'
-Revenge of the Sith
'
he knew every weakness of the Ataro form, with its ridiculous acrobatics. He drove a series of flashing thrusts toward Kenobi's legs to draw the Jedi Master into a flipping overhead leap so that Dooku could burn through his spine from kidneys to shoulder blades-and this image, this plan, was so clear in Dooku's mind that he almost failed to notice that Kenobi met every one of his thrusts without so much as moving his feet, staying perfectly centered, perfectly balanced, blade never moving a millimeter more than was necessary, deflecting without effort, riposting with flickering strikes and stabs swifter than the tongue of a Garollian ghost viper'
-Revenge of the Sith