Real Madrid suffered their first Champions League group defeat in five years after they were comprehensively beaten 3-1 by Tottenham Hotspur.
Dele Alli's brace and a Christian Eriksen effort not only sent Tottenham into the knockout stages on Wednesday but also earned them their first win against a Spanish side for the first time since a 5-1 victory over Atletico Madrid in the 1963 Cup Winners' Cup Final.
Harry Kane missed Tottenham's 1-0 defeat to Manchester United over the weekend with a hamstring injury, but the striker was back up top, alongside Christian Eriksen and Alli, who missed the match at the Santiago Bernabeu a fortnight ago.
Elsewhere for Mauricio Pochettino's side, Davinson Sanchez came into central defence, as did Kieran Tripper at right-back, and Eric Dier reverted to midfield.
Madrid, meanwhile, lost Varane to a muscle problem, so Nacho Fernandez partnered Sergio Ramos at centre-back.
Other than that, plus the continued absence of goalkeeper Keylor Navas, it was a full-strength Blancos XI, although Mateo Kovacic and Dani Carvajal were still missing, while Gareth Bale failed to make even the bench against his former club.
The two sides drew 1-1 the last time they met, but the winners in London would qualify for the knockout stages if Borussia Dortmund-APOEL ended in a draw.
Kane wasted no time in running on to a diagonal through ball, but his chipped effort at goal was saved by Casilla.
Indeed, Tottenham dominated the opening stages as the Madrid goalkeeper missed Kieran Trippier’s cross-shot from a diagonal pass, yet it also evaded a teammate.
Marcelo’s sliding clearance then turned into an inch-perfect cross for Harry Winks, but he miskicked and ended up clipping a tame shot at Casilla from a tight angle.
The hosts were forced into an early change as Moussa Sissoko replaced Toby Alderweireld, who went off clutching his right thigh, but just three minutes later, Alli slid home from a yard out to cap off a sweeping Spurs move.
Casemiro pushed for an equaliser, veering in from the left and angling a low shot towards Hugo Lloris’ bottom right, but the goalkeeper just about got a hand to it.
Cristiano Ronaldo’s profligate start to the season continued as he failed to beat Lloris with a series of snapshots, although the Frenchman needed to be at his best to tip the No 7’s half-volley around the post.
Karim Benzema was given an ideal platform to silence his critics, namely former Barcelona striker-turned-TV presenter Gary Lineker, but he hesitated when he led a counterattack, giving the Lilywhites enough time to block the No 7’s finish from his delayed cross.
Benzema did better when a second chance fell his way, rifling a volley on target from the edge of Tottenham’s box, but that was to be his final involvement.
Madrid began the second half by piling on the pressure, yet Marcelo’s cutback – while beating Lloris – was calmly dealt with by Eric Dier on the line.
That was followed by Alli shaking off Casemiro, not once but twice, before blasting a shot that deflected off Sergio Ramos and into the back of Casilla’s net.
An almighty goalmouth scramble saw Spurs suddenly hang on for dear life, but they eventually denied Ronaldo from a yard out, and more calamitous Madrid defending let Alli cut the ball back to an unmarked Eriksen, who clipped his finish past Casilla.
Barely a minute after Alli should have got his hat-trick after he failed to connect with Trippier’s cross, despite being unmarked, Ronaldo smashed in a close-range effort via Dier to make for a nail-biting finale at Wembley.
Nonetheless, Tottenham showed real resolve to contain Los Blancos’ late push and should’ve made it 4-1 when substitute Fernando took too long to lift the ball over Casilla in a one-on-one.
Madrid must now beat APOEL in three weeks’ time to book their place in the last 16 but risk going through as runners-up in Group H.
Tottenham Hotspur 3-1 Real Madrid
Alli 27, 56, Eriksen 65 (TH) Ronaldo 80 (RM)
Tottenham Hotspur: Lloris; Alderweireld (Sissoko 24), Davinson, Vertonghen; Trippier, Winks (Dembele 66), Dier, Davies; Eriksen, Kane (Llorente 79), Alli
Real Madrid: Casilla; Achraf, Nacho, Ramos, Marcelo; Modric (Theo 81), Casemiro, Kroos; Isco (Asensio 74); Benzema (Mayoral 74), Ronaldo
Referee: Cakir (TUR)