Valencia hopes suffer setback
The young forward, who has struggled after his breakout in 2011-12, came on as a second-half substitute and curled a loose ball into the corner of the net for the winner in the 79th minute.
Valencia outplayed Bilbao at San Mames Stadium throughout the second half, with Roberto Soldado scuffing a shot over the bar from inside the six-yard box in its best chance in the 83rd.
A week after he scored his first league goal of the season as Mallorca came from behind to win at Granada, the forward netted in each half to move his side up to third bottom, just one point from safety.
Alvaro Negredo briefly levelled for Sevilla just after the hour mark, but, with the lively Giovani Dos Santos causing plenty of problems, the hosts fully deserved their win.
They finished the match with 10 men after the sending-off of Javi Marquez for a second yellow card in the third minute of stoppage time, but by then the work was done.
Manuel Pellegrini fielded an under-strength side, presumably with the club's Champions League last-16 second-leg match with Porto on Wednesday in mind, resting Isco and Joaquin.
However, his team got off to a great start when Martin Demichelis headed them into the lead after eight minutes, but Manucho equalised for the hosts shortly before half-time.
An early goal by Chori Dominguez gave the Madrid side the perfect start and Piti wrapped up the points by netting on 77 minutes.