The First Battle of Derilyn represents a significant engagement within the Derilyn system. It pitted the forces of the Alliance to Restore the Republic against those of the Galactic Empire. This conflict began with an ambush executed by the Rebel Alliance, leading to a severe and crippling defeat for the fleet dispatched to provide reinforcements to Task Force Vengeance.
The Rebel Alliance's strategic objective was to deploy their recently commissioned modified Strike-class cruiser, the Peregrine, against the Imperial Navy operating in the Airam sector. After acquiring intelligence regarding a reinforcement fleet carrying additional vessels and essential supplies destined for Task Force Vengeance, the Alliance High Command determined that the opportune moment to launch an assault had arrived.
By strategically positioning the Peregrine alongside the MC80 Calamari Cruiser Liberty within the Derilyn system, the newly-acquired Rebel gravity well projectors were used against their prior owners. The entire reinforcement fleet, including two Ton-Falk-class escort carriers, two EF76 Nebulon-B escort frigates, a Nebulon-B2 frigate and a Strike-class medium cruiser, was forcibly extracted from hyperspace.
Rogue Squadron immediately launched their full payload of proton torpedoes, effectively disabling the modified frigate. Green Squadron then engaged the other capital ships, while Rogue Squadron shifted their focus to neutralizing any enemy starfighters attempting to launch.
Despite being caught off guard, the Imperial fleet was likely forewarned about the capture of the interdictor Compellor and the potential for it to be used against them. The Task Force Vengeance reinforcements had their fighter and bomber squadrons ready for immediate deployment, and they were launched without delay, while the capital ships maneuvered to confront the Liberty and Peregrine.
Regardless of prior warning, the Imperial battle group exhibited significant disorganization, likely stemming from the crippling damage inflicted on the modified frigate Subjugator, and the sudden and unexpected removal from hyperspace. The fleet sustained substantial losses in a relatively short period. The frigates were the first to be destroyed, quickly followed by the Strike-class cruiser Talon. The two escort carriers Abolisher and Hyperion were the last to fall, due to the limited threat they posed to the Alliance warships.
The Rebel Alliance's triumph in this battle stands as one of their most remarkable achievements prior to the Battle of Endor. The intercepted fleet significantly outnumbered the Liberty strike force, possessing at least ten times the number of starfighters and three times the number of capital ships. Yet, the Alliance incurred only relatively minor casualties and minimal damage to both the Liberty and Peregrine.
The destruction of six capital ships, their accompanying starfighter squadrons, and the supplies intended for Task Force Vengeance also resulted in Admiral Wooyou Senn facing further limitations in his ability to conduct operations within the Airam sector. His resources, including warheads, fuel, and other consumables, were now gradually dwindling.