Ancillary services improve grid resiliency by encouraging the active participation of consumers and suppliers in the supply demand matching process. We focus on the frequency regulation ancillary service, which allows large consumers to provide real time grid support by modulating their energy consumption according to grid requirements. State of the art regulation service providers implement frequency support using a fast response battery of large capacity, which absorbs or emits energy in response to the requests from the grid. Although data centers (DC) can provide similar services by exploiting workload elasticity, their slow response time severely limits the ability to provide real time support. In this paper, we develop a coupled DC and battery system which allows a data center to work in conjunction with a small battery to provide fast frequency regulation. Our system eliminates the need for large batteries and solves the issue of slow DC response time. By careful job scheduling through a Lyapunov control mechanism, we show that the DC can act as a virtual battery to amplify the regulation capacity of the physical battery. Our simulations show that the proposed system obtains up to 3.75x reduction in battery size compared to a standalone battery, without affecting the regulation capability. Our system delivers up to 28x improvement in the number of regulation response violations, compared to a standalone battery of similar size.