A single Star Destroyer (Imperial class II) with its complement of 72 Tie fighters vs 3 Mercury class Battlestars (Pegasus type).
Mercury class Battlestars are newer, more advanced, larger, and more powerful than the Galactica type battlestars. For those of you that have watched the TRS (the re imagined series) these are the same type of ship as the Battlestar Pegasus. Each has around 200 Viper Mk VII's, so with 3 a total of 600.
The Battlestars catch the Star Destroyer (it has it's shields up though), and launch most of their vipers as soon as they arrive while the Imperials man their stations.
Average Pilots on both sides
Win by destruction of all enemy ships