However, despite also leading 3-0 from their first leg win in Vallecas, Rayo faced a tougher tasker to grab a final place up against local rivals Leganes.
After falling behind to an early goal at the Estadio Butarque, Rayo rallied themselves after the break, to seal a 2-1 win on the night and a 5-1 victory over two legs.
— Rayo Vallecano (@RayoVallecano) June 6, 2021
Rayo and Girona are now bidding for a place in the top-flight for the first time since 2018 following their joint relegation at the end of 2018/19.
The final will be played over two legs across the next two weekends with Rayo at home on June 13 followed by a trip to Catalonia on June 20.
Images via Rayo Vallecano CF on Twitter