The champions' victory denies leaders Real Madrid the chance to take the crown by simply beating Cadiz next Saturday. 'Los Blancos' are 11 points clear of Barcelona with five matches remaining. Fermin Lopez sent the hosts ahead before Valencia striker Hugo Duro levelled and Pepelu netted from the spot to turn the game round.
Valencia goalkeeper Giorgi Mamardashvili was sent off late in the first half for handball and Lewandowski equalised soon after the break before adding another two late on. It rained all day in drought-ridden Barcelona and the threat of a soaking left the Olympic Stadium half empty, with an attendance of 30,000.
The small crowd might also have been a response to last weekend's Clasico defeat, which laid out the red carpet for Real Madrid to whisk away Barcelona's title, as well as the detested Monday night slot.