Real Madrid suffered their ninth La Liga loss of the season and their first under the returning Zinedine Zidane after being outclassed by Valencia.
They have now lost as many league matches this term as in their previous two campaigns combined.
Goncalo Guedes side-footed in a finish for the hosts in the first half and Ezequiel Garay headed in the second.
Karim Benzema pulled a goal back in injury-time for Real, but there was no time remaining to claim a point.
Up until Frenchman Benzema’s header in the 93rd minute, Real created very little and were second best throughout the match – their only effort of note was Toni Kroos’ long-range strike in the first half, which was easily dealt with by goalkeeper Neto.
With eight games remaining, Real are in third place, 13 points behind league leaders Barcelona. Meanwhile, Valencia move up to fifth place, just one point behind Getafe in fourth.
After Portuguese winger Guedes opened the scoring in the first half, exchanging passes with Carlos Soler and converting a smart finish at the near post, the home side had numerous opportunities for a second.
Geoffrey Kondogbia scooped over from close range, former Bolton loanee Rodrigo twice curled wide and Real goalkeeper Keylor Navas saved well from Soler’s breakaway run.
But Argentine defender Garay did double the advantage in the 83rd minute with a thumping header and although Benzema netted for the visitors, they were unable to emulate Barca’s epic late comeback in their 4-4 draw against Villarreal on Tuesday.