Three goals in the space of eight minutes lifted Palace out of the bottom three as Spurs lost their second match on the spin, although they could be forgiven for last week as it was after all against Chelsea.
Spurs target Routledge had a poor first half but improved steadily after the break and laid on the second for Danny Granville.
Only a few minutes earlier Mikele Leigertwood had headed the Eagles in front and Andy Johnson rounded off the afternoon with a penalty 15 minutes from the end.
The first half was somewhat disappointing with neither side claiming authority. The efforts at goal were even stevens while in terms of possession possibly Palace had the edge.
Dougie Freedman was recalled to the side for his third start of the season and started brightly with a couple of clever runs and crosses into the box but Spurs scrambled clear what Palace had to offer.
After the early huff and puff subsided, and courtesy from a deflection off the referee, Jermain Defoe had the first chance but lobbed his shot over.
Swiss international Reto Ziegler, who later retired with a hamstring injury, struck a free-kick just over before forcing Gabor Kiraly into making his first and only save on 20 minutes.
At the other end Granville was also presented with a free-kick on the edge of the box, and although his shot curled past the Tottenham wall, Paul Robinson was alert enough to stop at the foot of the post.
Leigertwood fired over once again but his luck was to change after the break.
Routledge pepped up a bit and struck a beautiful cross into the goalmouth which just eluded Freedman while for Spurs substitute Timothee Atouba did well with a low cross but it drifted across the face of the goal with no-one poised to follow up.
But the North Londoners were getting sloppy and one could sense Palace at last were gaining control.
Freedman played a neat pass to Tom Soares out on the left touchline. The Palace youngster wasted no time finding Leigertwood with a pinpoint cross and he thumped a far-post header home for his first Palace goal.
That came on 67 minutes and was the start of a triple goal-rush from the Eagles.
Five minutes later Granville added a second. Routledge provided the assist with a fine pass which split the Spurs defence for Palace full-back Granville to latch onto and drive a low shot from 12 yards out past the advancing Robinson.
Iain Dowie's outfit were on fire and within another three minutes put the match beyond Spurs reach.
Andy Johnson picked up a pass from midfield just outside the Spurs area. He cut inside and turned past two defenders before Dean Marney pulled down the Palace hit-man.
Johnson picked himself up and made no mistake from the spot with a fierce right-foot strike which flew past Robinson's outstretched right hand.
Spurs were shattered and it could have got worse. Leigertwood had another effort blocked and then Johnson was put through by Freedman but scuffed his shot.
MAN OF THE MATCH: Michael Hughes (Crystal Palace) – The midfield dynamo was behind much of Palace's best work as Iain Dowie's side cruised to victory.