His conventional Susanoo does have a chance against the Bijuu form, but he will most likely lose in the end since Susanoo requires a lot of chakra (which Sasuke doesn't have at this moment) and the Bijuu mode has full access to the tailed beast's chakra... well, half of it. Also, even if Sasuke survives the attack, it would probably kill him if it hits him. However, there is a technique called "Susanoo no Jutsu" which allows its user to destroy any one-tailed bijuu with just his mind. Since Kakashi is already using this technique, it means that even if Sasuke doesn't have any chakra left, he could use it anyway by thinking about his enemy and boom! Both tails are gone! So yes, Susanoo is stronger than Bijuu mode.