Rivals Lecce won 2-0 at already-relegated Bari in a fiery local derby, including minor crowd trouble. to help condemn Sampdoria with one round of matches still to play.
The Genoa side, last relegated in 1999, started the season in the Champions League qualifiers but sank like a stone after selling top strikers Antonio Cassano and Giampaolo Pazzini in January when they were in comfortable midtable.
"We must acknowledge the errors and assume the responsilbity for all the mistakes that were made," Edoardo Garrone, son of owner Riccardo, told reporters.
"The only thing I can say is that the family will stick with Sampdoria."
Napoli, who went broke in 2004 and reformed in the lower leagues, drew 1-1 at home to second-placed Inter Milan to secure the third automatic Champions League spot and their first return to the European Cup since 1991.
Champions Milan were awarded the trophy on Saturday after a 4-1 win over Cagliari, having already sealed the scudetto.
Udinese recaptured fourth spot thanks to a 2-0 win at Chievo and have a two-point cushion over Lazio, 4-2 winners over Genoa on Saturday, in the final Champions League qualifying spot heading into the final weekend.
Lazio's city rivals AS Roma are now out of the running for fourth after Alejandro Gomez's stoppage-time strike sealed a 2-1 win for Catania and potentially ended interim Roma coach Vincenzo Montella's hopes of the job fulltime.
Seventh-placed Juventus endured another low point in their second straight season of woe with a 1-0 defeat at Parma where on-loan Juve winger Sebastian Giovinco scored against his parent club to leave coach Luigi Del Neri on the brink of the sack.
PALOMBO SOBS
Former European Cup finalists Sampdoria, who boasted the likes of Gianluca Vialli and Ruud Gullit in their pomp, stepped out at a nervous Marassi knowing they needed a win to give themselves any hope of surviving.
They went behind on halftime to Fabrizio Miccoli's goal but Jonathan Biabiany, one of a number of forwards who have failed to adequately replace AC Milan's Cassano and Inter's Pazzini, equalised soon after the break.
As Sampdoria desperately sought another goal, Mauricio Pinilla sent a dagger into their hearts with a late winner.
Sampdoria captain and Italy midfielder Angelo Palombo sobbed on the pitch at the end and went to apologise to the main group of ultra fans, who unsuccessfully demanded that owner Riccardo Garrone also come "in front of the stands" to say sorry.
Cesena were not safe heading into Sunday but left nothing to chance with a 1-0 home win over already-relegated Brescia.
