Gary Neville's future as Valencia manager hung in the balance after his side were beaten 1-0 by fellow strugglers Real Betis, suffering a fourth league defeat in nine matches.
Ruben Castro scored the only goal of the game on 49 minutes by pouncing on more slack defending from Valencia, who had Jose Luis Gaya sent off with five minutes remaining and then had a headed goal from Shkrodan Mustafi ruled out in stoppage time.
Neville's side are now just four points above the relegation zone, only five points better off than when he took the reins of the team two months ago.
Betis had been suffering a similar results crisis before the game, failing to win a league game since November, but they join Valencia on 25 points thanks to their first victory under interim coach Juan Merino.
Neville made four changes to the team humbled 7-0 by Barcelona and opted for a 4-2-3-1 shape with Alvaro Negredo as the lone striker, while 22-year-old Wilfried Zahibo lined up in a holding midfield role alongside Dani Parejo.
Valencia were far more organised as a result, but struggled to create much. Their only attempts in the first half were poorly executed effort from Mustafi, who attempted to flick the ball towards the goal with his heel following a free-kick, and a distance effort from Parejo which went well wide.
The visitors did concede plenty of fouls, though, picking up four bookings before the break. They were also fortunate to make it into the break level, as Betis finished the first half strongly.
Norwich reject Ricky Van Wolfswinkel had the best chance of the half, getting through into the area but shooting straight into the arms of Mat Ryan.
Valencia had their first proper chance early in the second half, with Negredo released on the left hand side of the area and pulling his shot wide of the far post.
Then Betis attacked and made no mistake. Castro began the move in the final third and a flick by Charly Musonda helped it on to Van Wolfswinkel, whose low cross bypassed Aymen Abdennour and Castro swooped to tap in.
Valencia almost equalised immediately. Andre Gomes drove the team forward and slipped a pass to Denis Cheryshev, who cut it back to Negredo by the penalty spot, but Juan Manuel Vargas slid in to block the shot on the goalline.
Betis had further chances to stretch their lead, Alfred N'Diaye headed over the bar and then Vargas had a free-kick deflected wide. They looked to have finally got a second when substitute Jorge Molina leaped to head a free-kick into the far corner, but the goal was chalked off for a foul.
After breathing a sigh of relief at a disallowed goal, Valencia were then cursing their own bad luck as Mustafi was harshly ruled offside as he headed in from a free-kick. They could still have equalised in stoppage time even though they were a man down when Rodrigo was put through, but his shot was saved by Antonio Adan, leaving Neville on the brink.