A calamitous display from Vlad Chiriches eventually undid all of goalkeeper Hugo Lloris' good work as a last-gasp penalty earned Besiktas a hard-fought Europa League draw at Tottenham.
Spurs came into the match buoyed by Saturday's draw at bitter rivals Arsenal - a team Slaven Bilic's side pushed close in this season's Champions League play-offs.
Defeat to the Gunners saw the Turkish outfit drop into the Europa League, where they looked set to suffer more north London frustration until Demba Ba's last-gasp penalty cancelled out Harry Kane's 20-yard strike to secure a 1-1 draw.
Chiriches was guilty of giving away the spot-kick with a foolish handball when trying to make amends for an initial air kick, allowing the former Chelsea striker to finally beat Lloris.
The only survivor from the north London derby team, the France keeper was involved from the outset and produced a wonderful fingertip save to push an early Ba effort on to the woodwork.
It allowed Spurs to take the lead against the run of play when Kane scored with the host's first shot of the night in the 27th minute, with Lloris denying Olcay Sahan a quick leveller with an outstretched leg.
The keeper continued to shine in the second half, producing exquisite stops to again thwart Sahan and Ba.
Kane came close to a goal at the other end, but Besiktas continued to press and got a deserved equaliser when Ba slotted home after Chiriches capped a woeful display with a handball.
Bilic's side threatened from the very start at White Hart Lane, with Sahan coming close to capitalising on a Chiriches mistake inside 90 seconds.
It was a let-off for the Romania international, who was given a bloody nose after being caught by Ba's elbow soon after.
The Senegal striker received a yellow card and was soon joined in the referee's notebook by Ben Davies -- a player the Besiktas' danger man soon left helpless.
After vocal handball appeals were ignored the ball was swung into Ba, who flicked past Davies and impressively managed a strike Lloris did well to tip on to the bar.
Gokhan Tore, another former Chelsea player, was next to threaten as the Kara Kartal continued to dominate play, with Spurs not only struggling at the back but also to create any clear-cut chances.
In fact, it took 27 minutes for Pochettino's men to muster their first shot -- but when it came, it was a strike to remember.
Nabil Bentaleb played through Kane after a neat turn, with the forward bursting forwards before catching out goalkeeper Tolga Zengin with an early fizzing left-footed strike from 20 yards.
It was a sucker punch Bilic's men would have responded from immediately was it not for a world-class save by Lloris, whose foot managed to stop Sahan turning in a Jose Sosa cross at the backpost.
The game was by now a more even fare and, shortly after heading over, Kane stung the palms of Zengin after being put through by a neat Andros Townsend flick.
Things continued in a similarly-even fashion when play resumed for the second half, with Townsend curling over and Bentaleb drilling wide, as Lloris again saved the day.
Chiriches, as was becoming a common theme, was caught out and Ba slipped in Sahan, whose strike was bound for the top corner until the Spurs interjected.
An audacious Sahan overhead kick flew wide as Besiktas continued their search for a leveller, with substitute Mustafa Pektemek heading over before Lloris came to the rescue once more.
Chiriches' torrid night continued as a cross floated over him to Ba, who followed up a neat first touch with a close strike that was tipped over.
Besiktas goalkeeper Zengin had to produce a fine one-handed stop to deny Kane in the midst of that, but by now the visitors were on top.
Ba headed over as Bilic's side pressed intensely in the final quarter of an hour, finally breaking the deadlock thanks to another Chiriches mistake - giving away an 89th-minute penalty and earning a booking for handling the ball when attempting to make up for an air kick.
Ba stepped up for the resulting spot-kick and coolly slotted past Lloris to send the raucous travelling fans into raptures, frustrating Pochettino's men.