The Battle of Esfandia was the final rout of the Yuuzhan Vong fleet under B'shith Vorrik. Vorrik's fleet had been detailed to subdue the Imperial Remnant, and although Vorrik won the initial battle, the Imperial Starfleet under Grand Admiral Gilad Pellaeon had been slowly wearing down the Vong fleet ever since.
Esfandia was the final battle of that campaign, resulting in a massive Imperial rout of the Vong. Pellaeon's decisive victory was due in part to him having enraged Vorrik via verbal sparring ahead of the fight. After the Jedi Tahiri Veila convinced Vorrik to send some of his forces to the planet's surface, the reduced Vong complement was no match for the Imperial fleet. Knowing he was about to lose, Vorrik attempting to ram his ship, the Kur-hashan, into Pellaeon's command ship, the Right to Rule. However, the Kur-hashan detonated well before its target.
The Imperial routing of Vorrik's forces, and the end of the threat to the Remnant, freed up the Imperial Starfleet to fully assist Galactic Alliance forces in their fight against the wider Yuuzhan Vong threat.