Crystal Palace ended Tottenham's hopes of the treble with an unexpected 1-0 win at White Hart Lane that took them into the FA Cup quarter-finals.
An unlikely goal on a rare start for Martin Kelly, coupled with a vastly-improved overall performance, proved enough to secure a victory that will lift the mood that had been settling at Palace and inflict a rare disappointing note on Spurs so-far promising season.
With Tottenham also challenging for the Premier League title and Europa League, manager Mauricio Pochettino chose to again rotate his team from that which had drawn 1-1 at Fiorentina on Thursday.
Harry Kane, Kyle Walker, Danny Rose, and Eric Dier were recalled to his starting XI, while goalkeeper Michel Vorm retained his place in the absence of the injured Hugo Lloris and there were also rare starts for Josh Onomah and Nabil Bentaleb as Christian Eriksen and Toby Alderweireld were rested.
Palace's only victories in 2016 had come in the Cup. They had lost to Spurs in the Premier League only a month ago, and after this week taking his team to Spain for a training camp to prepare for this fixture, manager Alan Pardew surprisingly set his team up in a 4-4-2 formation, pairing Connor Wickham with former Spurs striker Emmanuel Adebayor in a front two and recalling the fit-again Joe Ledley.
As far as solutions to poor runs go - they had last won in the league on December 19 at Stoke - it was far from inspirational, but even then it surprised when Kelly began to emerge as the possible match-winner.
The full-back last played at former club Liverpool in November and was only selected in the absence of the suspended Pape Souare, though will know the in-form Spurs could easily have built an early lead.
Yohan Cabaye blocked a Dele Alli header off the line in the opening minutes, and though Walker almost headed an own goal over Vorm in the 14th minute - requiring the goalkeeper to recover and palm clear - Spurs' threat remained greater.
If the hosts were then fortunate, they were far less so with another effort from Alli in the 23rd minute. Son Hueng-Min broke down the left wing, and after Damien Delaney dispossessed him, Alli collected the loose ball before curling against the far right post, watching the ball roll along the line before hitting the other and then being cleared off the line by Joel Ward.
On the stroke of half-time, however, shortly after Kane had tested Wayne Hennessey with a 30-yard free-kick, Palace's, and Kelly's chance arrived almost from nowhere.
Wilfried Zaha drew Rose out of position, and with Kelly overlapping on the right-wing, played the full-back into the area from where he impressively and powerfully struck high inside Vorm's near post.
Though Spurs could do without further fixtures in their already busy schedule - and a replay was surely the last thing Pochettino wanted - he turned to substitutes Eriksen, Nacer Chadli and Ryan Mason in his pursuit of victory.
Yannick Bolasie, who had been missing since December 19 with a hip injury, returned as a second-half sub for Palace, creating a chance which was disallowed after the offside Wickham turned it into the net. They thereafter defended resiliently, securing the clean sheet which took them into the competition's last eight.