The space conflict known as the Battle of Delalt, alternatively referenced as the Battle of Dellalt, involved combatants from the Alliance to Restore the Republic and the Galactic Empire. A quartet of Rebel squadrons—Blue Squadron, Gold Squadron, Rogue Squadron, and Red Squadron—launched a starfighter assault against the Victory-class Star Destroyer named Formidable within the confines of the Delalt system.
Within the Rebel forces, two of the squadrons, specifically Blue and Gold, were outfitted with RZ-1 A-wing interceptors. These A-wings represented advanced iterations of the R-22 Spearhead, a craft previously flown by Keyan Farlander during a reconnaissance mission in the star system approximately three years prior. The remaining two squadrons, Rogue and Red, operated T-65 X-wing starfighters, each armed with a pair of sophisticated proton torpedoes. Their designated objective was to engage and attack the Victory-class Star Destroyer. As the four squadrons entered the system, they found themselves approximately one minute outside of warhead range from the Formidable. The Star Destroyer promptly initiated target locks on the approaching starfighters, utilizing its concussion missile launchers to fire missiles from a distance. Furthermore, the Victory-class Star Destroyer deployed its full complement of TIE/IN interceptors. The TIE pilots, potentially assessing the opposition as formidable, may have requested reinforcements from Tau Squadron, which was stationed nearby in Assault Gunboats on standby.
Given the Formidable's robust defenses against starfighter attacks and the aggressive tactics of its TIE pilots, coupled with the limited warhead payload carried by the Rebel strike force, it is plausible that at least one flight group from Green Squadron, another X-wing unit operating in the sector, arrived to provide support in the engagement. The elimination of the Formidable held crucial importance for the Alliance, yet the Rebels faced the constraint of not being able to afford the loss of more than two-thirds of their starfighters during the conflict. The TIE interceptors assigned to the Formidable bore the responsibility of inflicting substantial casualties and compelling the Rebels to retreat, or at the very least, preventing the destruction of their command ship until the Imperial Nebulon-B frigate named Fury could arrive to offer assistance.
The Battle of Delalt seemingly marked the concluding action of Operation: Clean Sweep.
Within the computer game Star Wars: X-Wing vs. TIE Fighter, players have the opportunity to participate in the mission titled "Attack on Victory-class Star Destroyer Formidable" from either the Rebel or Imperial perspective. This results in conflicting mission objectives for each side. Furthermore, since achieving victory is not a prerequisite for progressing to the subsequent set of missions, the battle itself is considered canon, but the specific canonical outcome remains undetermined.
The ships detailed in this article are those present during the Operation: Clean Sweep battle, utilizing the default craft assigned to the player.
The Delalt system, as referenced in the mission description and briefings for "Attack on Victory-class Star Destroyer Formidable," is highly likely the same as the Dellalt system featured in Star Wars: X-Wing. Both the Caluula sector and the unnamed sector containing the system featured in this mission were seemingly either under Rebel Alliance control or exhibited a significant Rebel presence during at least a portion of the period between the Battle of Turkana and the Battle of Endor. It appears improbable that the Rebels would maintain control over two distinct sectors containing star systems with such similar names. Additionally, it is unlikely that the game designers of X-wing vs. TIE Fighter, many of whom transitioned from the team responsible for X-wing, would have intended these to be separate systems.
The battle was apparently the last of the Imperial Operation: Clean Sweep. This suggests that the Formidable was present in the system (which the Rebel mission briefing refers to as in "our Sector") conducting an offensive. A Rebel counterattack following the Imperials' conclusion of the operation would likely not be considered its final battle (unless it was so decisive as to force the Empire to abort the operation, which seems unlikely even assuming the total destruction of the Formidable, the Fury, and all Imperial starfighters in this battle).