Liverpool boss Arne Slot slammed the controversial decision not to send off Tottenham's Lucas Bergvall before the teenager sealed a 1-0 win in the League Cup semifinal first leg on Wednesday.
Slot was furious that Bergvall avoided a second booking after tripping Kostas Tsimikas with a sliding tackle.
Tsimikas was forced off the pitch following the challenge but referee Stuart Attwell opted to give Liverpool the chance to counter-attack.
When Liverpool lost possession just seconds later, Tottenham took advantage by breaking into the space vacated by Tsimikas to score the 86th minute winner.
Dominic Solanke's pass was converted by Bergvall for the 18-year-old's first Tottenham goal.
But fuming Slot said: "The decision made had a lot of impact on the result tonight.
"The fourth official told me why he thought it wasn't a second yellow and he heard that probably from the referee.
"What we can say about it is that he said he didn't stop the counter-attack, every manager would say they prefer the second yellow than a free-kick.
"Spurs weren't happy with a few decisions that happened (against Newcastle) on Sunday. Maybe today a decision went in favour of them, which is of course very unlucky for us."
Inevitably, Tottenham manager Ange Postecoglou saw the incident differently.
Asked if Bergvall was lucky to avoid a red card, Postecoglou said: "Great question, no he wasn't.
"It's happened to us consistently, you look at our games, and we've asked the officials and they've said if you play advantage, as long as it's not a cynical tackle, then yellow card doesn't get shown. Now to me, that was pretty clear."
POSTECOGLOU RELIEF
It was a cathartic victory for Postecoglou, who has been under fire from frustrated fans throughout a turbulent season.
Injury-hit Tottenham are languishing in 12th place in the Premier League amid criticism of the Australian's overly-attacking tactics.
Postecoglou, who saw his injury problems mount when Rodrigo Bentancur was taken to hospital with a head injury suffered in the first half, admitted it was a relief to see his side overcome adversity for a change.
"Very proud. We had to deal with some adversity again. We started well and then lost Rodrigo, in the way it happened with quite distressing scenes when he went down in that manner. We had to compose ourselves," he said.
Postecoglou's claim earlier this season that he always wins a trophy in his second campaign with a club has been used to ridicule the former Celtic boss as Tottenham's struggles increased.
But he is convinced Tottenham are heading in the right direction as he tries to bring the club their first silverware since the 2008 League Cup.
"People can keep mocking me about it but we will see," he said.
"We haven't achieved anything yet, just that feeling of getting a result in a big game against arguably the best team in the world right now."
On Bentancur's first half injury, which needed nine minutes of treatment including an oxygen mask on the pitch, Postecoglou added: "He was conscious when he got to the dressing room.
"My understanding is it was a head injury. It was worrying and always a concern but from what I know hopefully he will be okay."
Liverpool's first defeat in 24 games in all competitions was only their second loss since Slot replaced Jurgen Klopp in the close-season.
The Premier League leaders have gone two matches without a win after Sunday's disappointing 2-2 draw with lowly Manchester United.
But Slot, whose team won 6-3 at Tottenham in the league in December, isn't overly concerned, with Liverpool having the chance to overturn the deficit in the second leg at Anfield on February 6.
"The good thing for us is if you ever lose a game it's best in a tie with a second leg. It's still far from ideal for us," he said.
"If you compare it to the 6-3, we won't reach that level in every game. You could expect a reaction from Tottenham."