There's certainly a chance for Kenobi. He's in his physical prime, utilizing the same aggressive form as Anakin, and has the same amount of experience (I think it's three saber duels to one in his favor). I see Anakin winning more often than not though. He's stronger, made Dooku more hard-pressed to defeat him than even the AOTC Kenobi incarnation, and his reserves of the Force eclipse Obi-Wan's a thousand times over.