Fernando Torres marked his return to the Spain team with a well-taken double as the Republic of Ireland's Euro 2012 dream came to a painful end with a 4-0 defeat.
Torres struck after just four minutes and then again 20 minutes from time either side of David Silva's superb finish as the reigning champions completed a routine victory over Giovanni Trapattoni's men, with substitute Cesc Fabregas completing the job late on.
Victory over Croatia on Monday evening will ensure Spain top Group C, but Ireland are heading home regardless of what they do against Italy in Poznan.
Silva's fleet-footed burst into the penalty area prompted Richard Dunne to make a desperate and successful sliding challenge, but the ball dropped nicely for Torres to round full-back Stephen Ward and smash a right-foot shot from a tight angle high past goalkeeper Shay Given and into the roof of the net.
It was the last thing Ireland needed, although it came after Simon Cox, preferred to Kevin Doyle in a 4-5-1 formation, had tested Iker Casillas with a second-minute drive from distance. But Irish forays into enemy territory were to prove a rare occurrence as Spain, not unsurprisingly, dominated the middle of the field to lay siege to Given's goal.
The game was effectively over within four costly minutes as Spain once again flexed their muscles at the start of the second half.
Given had already repelled another effort from Alvaro Arbeloa when the keeper's attempt to keep out Andres Iniesta's powerfully-struck shot dropped to the feet of Silva. The Manchester City midfielder still had plenty to do, but he tip-toed his way through the wreckage of the Irish defence before slotting the ball calmly into the bottom corner.
Further damage was inflicted with 20 minutes remaining when Torres once again ran clear of a static defence to fire expertly past Given and finally kill off hopes of a fightback.
Torres departed to rapturous applause from his compatriots with 18 minutes remaining as Fabregas took his place with Spain already looking towards Monday night.
There was an equally warm welcome for James McClean when he was handed a second cap and a first competitive appearance as 76th-minute substitute, but Ireland's woes increased seven minutes from time when Fabregas blasted home a fourth as Giovanni Trapattoni's men slept at a corner.