Her skills haven't really improved upon what she had during the bell retrieval exercise after Naruto returned from his training with Jiraiya. Even with Naruto assisting her back then she wasn't making much headway with her battle with Kakashi, the only reason why they won was due to Naruto's observations of Kakashi's habits.
Sakura alone does not possess the skills to fight Kakashi one on one, he's got a more extensive variety of jutsu then she does and he's certainly got more field experience then she is. Her only probable chance of winning is if she pulled a Tsunade and laced his food or drink.