Valencia youngster Javi Guerra struck a vital stoppage-time winner to help his side beat Real Valladolid 2-1 on Thursday and climb out of LaLiga's relegation zone.
Los Che produced a fine comeback at Mestalla to pull themselves towards safety, up to 16th, two points above the bottom three.
Espanyol, 19th, sunk deeper into the mire with a 4-2 defeat by Villarreal.
Canadian striker Cyle Larin struck in the sixth minute after a lapse in concentration by Valencia defender Mouctar Diakhaby, who gave the ball away in his own half.
However the Guinea defender made amends for his mistake for Valencia on the hour mark.
Valladolid goalkeeper thought Diakhaby's header was going wide but it crept in for a bizarre equaliser.
With the clock ticking down it looked like Valencia would be held to a draw by Valladolid, 14th, who are not yet safe themselves.
However Guerra, 19, drove forward and fired into the top right corner on only his third LaLiga appearance.
"I thought of my whole family and the team, we deserved this victory," said Guerra.
"I'm from Valencia and to see Mestalla like this is so nice, this win is for the whole team."
Villarreal moved fifth with their entertaining victory over Espanyol.
Etienne Capoue struck twice for the Yellow Submarine, who kept the Catalans submerged, now four points from safety.
Javi Puado sent the visitors ahead on Spain's east coast but Capoue levelled, before Dani Parejo sent Villarreal ahead.
Joselu levelled for Espanyol but Nicolas Jackson struck in the 80th minute to tip the game back the hosts' way and Capoue made the game safe in stoppage time.
Edu Exposito was sent off for Espanyol at the death to compound the visitors' misery ahead of their key clash with fellow stragglers Getafe on Sunday.