On Sunday Tottenham lost to relegation-threatened Crystal Palace, sending their fans into meltdown, but supporters were singing loud and long after beating Manchester City, inflicting their first defeat since last May's FA Cup final.
Early goals from Timo Werner and Pape Matar Sarr put Spurs in control against an understrength City, who got one goal back in first-half stoppage time through Matheus Nunes, but could not find an equaliser.
Pep Guardiola had promised to rest some of his stars and the main omission was Erling Haaland, kept on the substitutes bench at the start. Reuben Dias should have been with him but was drafted into the starting line-up after an injury in the warm-up.
It was still a youthful line-up, with James McAtee and Nico O'Reilly given further chances to impress, which they did, and more teenagers introduced as substitutes.
Ange Postecoglou made changes too, and it was Tottenham who made a flying start, scoring after five minutes with a rare goal from Werner. The German has been short of form and confidence this season, but he finished emphatically from 15 yards after Spurs broke swiftly from defence to attack. Archie Gray combined with Brennan Johnson to send Dejan Kulusevski away on the right, and when the Swede curled a low cross to the far side of the penalty area, Werner beat Rico Lewis to the ball to sweep it powerfully past Stefan Ortega.
Spurs started like a steam train, determined to make up for their lacklustre loss at Palace, but their rhythm was disrupted when Micky Van de Ven limped off with a hamstring injury in the 13th minute. The big Dutchman looked close to tears, suggesting he knows he faces a lengthy lay-off.
But Tottenham extended their lead in the 25th minute with a well-worked goal. Werner and Kulusevski exchanged passes from a short corner before the Swede laid the ball into the path of Sarr, who curled home an exquisite shot from 25 yards.
The Tottenham Hotspur stadium was rocking, with home fans sensing an upset, especially as City had failed to force a save from Guglielmo Vicario during the opening 45 minutes, with Ilkay Gundogan and Phil Foden both putting free-kicks wastefully over the bar.
But in the fourth minute of stoppage time, they got a goal back through a combination of their wingers Savinho and Nunes, their best two players up to that point. Savinho wriggled free down the right, chipped a cross beyond the far post, and Nunes struck a volley into the turf and up past Vicario.
It had been an enthralling first-half, both sides zipping the ball about at pace, playing smart, passing football with clever movement, and it did not let up after the break. Spurs could have scored three goals on the counter-attack in the opening ten minutes, as Werner shot wide after running free from the half-way line, and then blazing high over the bar in the 55th minute. In between those attacks, Kulusevski, again Tottenham's best player, led another break and forced a fine low save from Ortega.
City suffered an injury blow of their own in the 62nd minute when Savinho was carried off on a stretcher after injuring an ankle. His replacement was another youngster, Jacob Wright, whose first involvement was to shoot just wide of the post.
Werner led yet another break without success before he, too, went off injured, this time to a rousing reception from home supporters, who had been critical of his performances in recent weeks.
The number of injuries will only fuel the fire of those critics who say too much is being asked of players, even when squad rotation is in effect as it was with both sides last night.
Tottenham have an important game against Aston Villa this weekend that could make or break their chances of qualifying for the Champions League, while City make the long trip to Bournemouth, who beat Arsenal last week.
The high-octane action did not let up, though. Richarlison, on as a substitute, was given a golden chance to make it 3-1 when Josko Gvardiol's throw-in landed at his feet 15 yards from goal, but the Brazilian shot straight at Ortega.
Vicario then flew across his area to clear a cross from the right, and from the ensuing corner, Yves Bissouma stuck out a foot to clear O'Reilly's goalbound volley off the line.
When six minutes of extra time was announced, home supporters feared the worst, having seen their side lose to a last-gasp winner by City in the FA Cup at this ground last January. This time Tottenham held on to move into the quarter finals of the Carabao Cup.
TOTTENHAM (4-3-3): Vicario 6 ; Gray 7, Romero 6 (Davies 52), Dragusin 7, Van de Ven 6 (Udogie 13); Bentancur 7, Sarr 7 (Bissouma 46), Kulusevski 8; Johnson 7 (Richarlison 68), Solanke 7, Werner 7 (Moore 68).
MAN CITY (4-3-3): Ortega 6; Lewis 7, Stones 6, Dias 6 (Gvardiol 46), Ake 6 (Simpson-Pusey 74); O'Reilly 7, Gundogan 6 (Kovacic 46), McAtee 6; Savinho 7 (Wright 62), Foden 6 (Silva 58), Nunes 7.
Ref: Robert Jones 7