It is business jargon. An employee who "delivers" means that the employee makes the company more successful. The company has set various goals for its employees. If the employee is delivering "against the goals" I would understand this to mean that they are being successful measured using the goals.
You use "against" when using something to measure with. For example "I measured Jane's height against her brother." It means that I compared Jane and her brother's heights to find who is taller. Measuring the employee against the goal means "I found if the employee is achieving the goals".