The win ensures Valencia progress as winners of group A, while Swansea will need at least a point at St Gallen to book their place in the prestigious tournament.
In a pulsating game both teams came out with intent from the off but the Spanish giants struck with the only goal of the night after just 21 minutes.
Swansea?s keeper Gerhard Tremmel failed to clear the corner and Dani Parejo made no mistake guiding home the ball after Juans Bernat?s deflected shot fell kindly to him.
Swansea however did have the ball in the back of the net, Alvaro Vazquez tapping in after Valencia?s keeper parried Jonjo Shelvey?s effort but the goal was deemed offside.
The Welsh side kept pushing and Jeremy Mathieu cleared Vasquez goal bound attempt of the line in the last minutes of the game.
The night became worse as injuries to striker Bony Wilfred and Angel Rangel adds to Micheal Laudrups woes with star striker Michu already out.
Source: DSG
Source: DSG