Just like last season against Middlesbrough, we bowed out after leading 1-0 and seemingly having a place in the semi-finals in our grasp.
However - as was the case again last season - Liverpool levelled with five minutes left on the clock, this time in extra time, before going through in sudden death.
Jermain Defoe, Michael Carrick slotted their penalties but Fredi Kanoute had his saved by Jerzy Dudek and Michael Brown cleared the crossbar before Reto Ziegler netted the fifth.
Paul Robinson saved Liverpool's third from Darren Potter but Florent Sinama-Pongolle - who netted Liverpool's equaliser from the the spot after 115 minutes - grabbed his chance to be the hero and the Anfield side went through 4-3.
Penalties looked an unlikely outcome after an hour of normal time and then again once Defoe had opened the scoring in the 107th minute but it wasn't to be.
We dominated the first hour to such an extent that Liverpool had just one shot of any note but our failure to breakthrough clearly gave the visitors confidence and they carved out the better chances in the final 20 minutes.
Liverpool had Dudek to thank for keeping the tie goalless with two saves from Robbie Keane - the second one of the best seen this season - while Kanoute hit the crossbar, Rohan Ricketts missed a free header in front of goal and penalty claims for handball were turned down.
As Liverpool opted for a mainly reserve side, Martin Jol went with Keane and Kanoute up front, Defoe on the bench, Anthony Gardner back for Noureddine Naybet and Brown in midfield.
We started well and Kanoute struck the top of the bar after typically chesting down, spinning and shooting as early as the fifth minute.
It was all Spurs as Ziegler hit the side-netting, referee Neale Barry waved away penalty appeals when Noe Pamarot's header struck Zak Whitbread's arm and then Ricketts failed to hit the target from eight yards after Kanoute's pinpoint cross.
Dudek reserved his best for Keane. The first save arrived after 36 minutes with a moment of Keane magic to leave two defenders on the floor only for Dudek to come out quickly and block from close range.
Into the second half and Keane had already hit the side-netting when Dudek produced his wonder save - Keane volleyed Kanoute's cross into the ground from all of six yards but Dudek was able to use the motion of the ball moving upwards to lift it over the bar.
Unfortunately, despite the arrival of Defoe, play started shifting the other way and Gardner had a look of relief when the referee chose only to book him after he slipped to allow Sinama-Pongolle through on goal and brought him down. Ledley King was over to cover and that saved the big defender.
That was on 78 minutes and Liverpool soon created their best chances as Sinama-Pongolle failed to pick out John Welsh and Mark Smyth in the box and then both Gardner and King blocked superbly to deny Igor Biscan and Welsh.
Both sides went close with curlers via Kanoute and Welsh at the start of extra time before the first real glimpse of Defoe, an injection of pace taking him clear only for David Raven to block.
Dudek made a couple of routine saves in the second half of extra time before the moment we'd all been waiting for.
With 107 minutes on the clock, Brown released Kanoute down the right, he picked out his strike partner's run to the near post and Defoe made no mistake - a carbon-copy of his goal against Middlesbrough on Sunday and his 11th of the season.
We had 13 minutes to hold but, as is always the case, we started to sit further and further back.
We were almost punished when Sinama-Pongolle got onto Welsh's cross just 10 yards out only for Robinson to make an outstanding point-blank save but Liverpool equalised from the resulting corner. Raven curled it in, Kanoute's hand connected accidently - he wasn't even looking at the ball - and Sinama-Pongolle slotted from the spot.
That was the last of the action and when Sinama-Pongolle stepped up again from 12 yards, he sent Liverpool into the semis.
GUIDE TO THE ACTION
1min: First effort, Ricketts badly sliced attempted shot from right corner of box.
5mins: WOODWORK. Kanoute controlled lovely Ziegler pass on chest, swivelled and struck crossbar from 10 yards.
6mins: Liverpool's first attempt, Potter won ball in midfield but hit shot high and wide.
9mins: Brown beavering away nicked ball off Henchoz but Kanoute sliced volley wide from 18 yards.
11mins: Good interplay between Kanoute and Keane but Keane's pass a yard too far for Ziegler and Dudek out to collect.
15mins: Kanoute wide to Ziegler, managed to nip around Raven before lashing shot into the side-netting.
19mins: PENALTY? Cries for spot kick waved away as Pamarot's header struck Whitbread's arm.
20mins: MISS. Ricketts failed to hit the target with free header from 10 yards after Kanoute's superb cross.
35mins: Ricketts drive across Dudek from 22 yards flashed a couple of yards wide.
36mins: SAVE. Liverpool failed to clear corner, Pamarot drove ball across goal to Keane, far post, two defenders charged him down but left them on floor with dummy only for Dudek to block shot.
37mins: YELLOW. Pamarot for foul on Sinama-Pongolle.
Injury-time: Ziegler free-kick heading for top corner but little pace and comfortable save for Dudek.
Half-time: Spurs 0, Liverpool 0
51mins: SUB. Welsh for Mellor.
52mins: Ziegler free-kick flicked over by Kanoute.
53mins: MISS. Keane did well to take possession of bouncing ball from Dudek but fired loose ball into side-netting from six yards.
55mins: Nunez dipping volley always just too high.
57mins: YELLOW. Welsh for foul on Atouba.
59mins: SAVE. Unbelievable reactions from Dudek. Ziegler broke from our half, released Kanoute down right, he skipped past Warnock and crossed to near post when Keane volleyed into ground from six yards, Dudek somehow managed to flick ball over.
65mins: SUB. Defoe for Ricketts.
69mins: SUB. Smyth for Nunez.
71mins: Robinson alive to Smyth shot to near post for first serious save of night.
78mins: YELLOW. Controversial incident as Gardner lost out to Sinama-Pongolle and then brought him down when he had a run on goal, King over to cover looked to have saved him from red card.
83mins: Half-chance as Sinama-Pongolle got to byline but pulled cross behind Welsh and Smyth.
84mins: Great block from Gardner as Biscan broke into box, then another from King as Welsh followed up.
85mins: SUB. Mendes for Keane.
Injury time: Kanoute on the end of Atouba's cross but not enough power to trouble Dudek.
Full-time: Spurs 0, Liverpool 0
94mins: CLOSE. Mendes into Kanoute who turned onto his left foot and curled just over from 20 yards.
95mins: CLOSER. Welsh curler from left corner of box inches wide with Robinson at full stretch.
100mins: BLOCK. First real glimpse of Defoe, sprinted away from Welsh, Henchoz slipped and was through on Dudek, pulled the trigger but Raven over to make superb last-ditch tackle.
Half-time, extra-time: Spurs 0, Liverpool 0
106mins: Good move started by Carrick, Kanoute into Defoe, left-foot curler from 20 yards too close to Dudek who made comfortable save.
107mins: Brown effort from 22 yards straight at Dudek.
107mins: GOAL. Brown fed Kanoute down left flank, ball cut back to Defoe to finish at near post, six yards out.
Spurs 1, Liverpool 0
110mins: SUB. Partridge for Diao.
114mins: SAVE. Robinson point-blank tip over to deny Sinama-Pongolle header.
115mins: PENALTY/GOAL. Kanoute handled from corner, Sinama-Pongolle slotted home penalty.
Spurs 1, Liverpool 1
Full-time, extra-time: Spurs 1, Liverpool 1
Defoe - SCORED - 1-0
Henchoz - SCORED - 1-1
Carrick - SCORED - 2-1
Partridge - SCORED - 2-2
Kanoute - SAVED - 2-2
Potter - SAVED - 2-2
Brown - MISSED - 2-2
Welsh - SCORED - 2-3
Ziegler - SCORED - 3-3
Sinama-Pongolle - SCORED - 3-4
Liverpool won 4-3 on penalties
Line-ups: Spurs (4-4-2): Robinson; Pamarot, King, Gardner, Atouba; Ziegler, Carrick, Brown, Ricketts (Defoe, 65); Kanoute, Keane (Mendes, 85). Subs: Fulop, Naybet, Redknapp.
Liverpool: Dudek, Henchoz, Diao (Partridge, 110), Nunez (Smyth, 69), Sinama-Pongolle, Biscan, Warnock, Raven, Mellor (Welsh, 51), Potter, Whitbread. Subs: Kirkland, Foy.
Referee: Neale Barry.
We suffered penalty agony again in the quarter-finals of the Carling Cup as Liverpool won Wednesday night's shoot-out at the Lane.