(AFP) - Gary Neville's winless streak in La Liga since taking charge of Valencia last month stretched to five games as Jonathas' late double handed Real Sociedad a 2-0 win on Sunday.
Neville's men had shown promising signs in holding Real Madrid 2-2 last weekend and a 4-0 thrashing of Granada in the Copa del Rey in midweek, but have now gone two months without a league win to almost certainly end their hopes of reaching the Champions League next season.
"It's a blow, we needed momentum, but we played well below the expectations we have set ourselves," said Neville.
"We have to snap out of it and start winning. I can only ask the fans to be patient. The dressing room is disappointed, as am I, but tomorrow is a fresh start and we have to get the fans to believe."
Valencia 'keeper Jaume Domenech had kept his side in the game for long spells after both sides hit the woodwork early on.
However, he was at fault when he flapped at Carlos Martinez's deflected cross and Jonathas bundled home from close range 12 minutes from time.
The same two players combined for the second four minutes later as the Brazilian thumped home the full-back's cross with a bullet header into the bottom corner.
Defeat leaves Valencia down in 10th, now 16 points off the top four after Villarreal beat Sporting Gijon 2-0 earlier on Sunday.
Cedric Bakambu struck twice as Villarreal moved to within three points of leaders Barcelona with their sixth successive La Liga win.
Former Tottenham Hotspur striker Roberto Soldado provided the ammunition for both his strike partner's goals with crosses that Bakambu clinically dispatched either side of half-time to take his tally for the season to 12.
Victory takes Villarreal eight points clear of Celta Vigo in fifth with the Galicians hosting Atletico Madrid later on Sunday.