Samantha Stosur inspired Australia to a 3-2 win over Spain in their Fed Cup World Group II first round tie at Memorial Drive here on Sunday.
The world number 11 Stosur featured in all three of Australia's victories and joined with 38-year-old veteran Rennae Stubbs to gain the winning doubles rubber in the final match.
Australia will now have an April play-off for elevation to the elite World Group for the first time since 2004.
Stosur, who lost to world number one and eventual champion Serena Williams in the fourth round at this month's Australian Open in Melbourne, won both her singles ties against Maria Jose Martinez Sanchez and Anabel Medina Garrigues.
Carla Suarez Navarro had levelled the tie on Sunday with a 6-1, 6-1 win over former world number eight Alicia Molik, who is on the comeback trail and is currently ranked 170.
But in the deciding tie, Stosur and Stubbs easily got Australia home with a 6-4, 6-2 win over Spanish pair Martinez Sanchez and Nuria Llagostera Vives.
Spain were Fed Cup champions five times in the 1990s but last year were relegated to the World Group II following losses to the Czech Republic and Serbia.
It was only Australia's third victory in 10 Fed Cup series with Spain.
