Leo Baptistao added a late winner to his first-half equaliser as Rayo Vallecano came from behind to beat Athletic Bilbao 2-1 at home.
Athletic were in front in the 20th minute through Aritz Aduriz's close-range finish.
But their poor start to the season continued after Baptistao, scoring his first goals since his return to Rayo over the summer, turned the game on its head. The on-loan Atletico Madrid forward pounced on a Gorka Iraizoz error to level in the 39th minute and then notched again in the 89th.
While this is the hosts' maiden victory of the season, it leaves Ernesto Valverde's visitors with a league record for 2014-15 so far showing four losses and one win from five games.
Athletic looked to exert pressure in the early stages and moments after Benat fired wide from a free-kick following Quini's foul on Iker Muniain, they took the lead.
Oscar de Marcos provided a precise pass across the box from the right which was met by the right foot of Aduriz, who swept the ball into the net.
Just prior to the half-hour mark Rayo boss Paco Jemez opted to make a substitution, replacing Quini with Tito at the back.
And the change seemed to work, with Athletic losing some momentum and Rayo equalising six minutes before the break in somewhat fortunate circumstances.
Lica sent the ball into the danger zone from the wing and when Iraizoz fluffed his attempted catch, allowing it to squirm beneath him towards the line, Baptistao slid in to finish.
Gael Kakuta then tried his luck on Iraizoz's goal only to shoot off-target, before Mikel Rico saw his reply for the visitors blocked by Abdoulaye Ba.
Rayo passed up a double opportunity to score just after the interval as Lica's shot was parried by Iraizoz and Kakuta sent the ball over the bar.
At the other end, Aduriz's strike was held by Tono, who had come on as a half-time substitute for injured stopper Cristian Alvarez.
A shot wide from another substitute, Borja Viguera, and header to Tono from Aduriz followed as Athletic sought to regain the advantage, before Roberto Trashorras and Alberto Bueno missed the target for Rayo.
As the game moved into its final five minutes, Aduriz nodded a Benat cross wide from inside the box, seconds before Irazoiz pulled off a brilliant save to keep out a header from the recently-introduced Manucho.
Two minutes after that, Rayo snatched the victory as Baptistao bundled the ball home from Kakuta's cross.
Aymeric Laporte subsequently headed a Benat corner wide in stoppage time and the three points were confirmed as Rayo's.
ends