Alaves secured their place back in La Liga on Sunday evening with a 2-0 win at home to Numancia.
The Basque side, who were beaten 5-4 by Liverpool in a thrilling UEFA Cup final in 2001, were last in the top flight in 2006 and spent four years in the third tier since then.
The club have only enjoyed 11 seasons in the top division in their 86-year history, but that will become 12 after first-half goals from Manuel Garcia and Raul gave them the victory they needed.
Alaves will seal the title with a point away to Gimnastic next weekend, but the home side must win to stand any chance of automatic promotion themselves. Gimnastic are a point behind second-placed Leganes going into the final round with an inferior head-to-head record. Leganes go to midtable Mirandes on the same day.
The top two teams in the Segunda are promoted automatically, with for other teams entering the playoffs for a place in La Liga.
There will be four Basque clubs in La Liga next season, with Alaves joining Athletic Bilbao, Eibar and Real Sociedad.