With Thursday's first leg in Elche finishing 0-0, the return clash in Catalonia also appeared set to finish without a goal in the regulation 90 minutes.
But Pere Milla headed in the decisive goal in the sixth minute of second-half stoppage time, as Elche made the most of their numerical advantage following the dismissal of Cristhian Stuani, who was shown a red card after a VAR review deemed he stamped on an opponent.
💚 𝑆𝑂𝑀𝑂𝑆 𝐷𝐸 𝑃𝑅𝐼𝑀𝐸𝑅𝐴 🤍😭 pic.twitter.com/Ax1eBSE6Pu— Elche Club de Fútbol 🚀🆙🌴 (@elchecf) August 23, 2020
Victory sees Elche return to LaLiga after five years away.
They were relegated from LaLiga in 2014-15 despite finishing 13th, as Elche became the first club in the division's history to be demoted due to their financial difficulties.
Since then, they have dropped as far as the third tier, but Elche now join champions Huesca and second-placed Cadiz in earning promotion to Spain's top tier.