We show the existence of an extremal 80-dimensional lattice that is even, unimodular, and whose automorphism group contains a copy of SL₂(F₇9). This lattice was constructed a few decades ago by Schulze-Pillot, and was given as a candidate for extremality (minimal norm 8). Although other 80-dimensional extremal lattices were known, the provenance for this one was yet unknown. Our method of proof involved the positivity of the Thets-series and finding over 7.5 trillion vectors of norm 10. This last step took about 2 cpu-months (4 days on a cluster), and made heavy use of new pruning methods for vector enumeration due to D. Stehlé.