Battle of Ord Biniir
this struggle was actually two battles, both of which took place during the Galactic Civil War. In the weeks leading up to the Battle of Yavin, the Alliance's Y-Wings managed to defeat the 223rd Imperial Fighter Group and take the planet Ord Biniir from Imperial control. (Note that this is most likely the battle that is referenced in the opening crawl of Star Wars: A New Hope.) Shortly afterward, on the very day of the Battle of Yavin, the 181st Imperial Fighter Wing managed to destroy the Alliance forces over Ord Biniir and retake the planet.