Ange Postecoglou went through the ringer once again. This time, the biggest controversy of the night went in his favour but not before he had thrown hands onto his head in disbelief and sunk to his knees in despair.

There was concern, too, for his Uruguayan midfielder Rodrigo Bentancur, carried off after appearing to be knocked unconscious, which was allayed by a positive update that he was conscious and talking at half time.

This time, Postecoglou emerged victorious with a smile on his face not a scowl. Punching the air as Lucas Bergvall's first Tottenham goal gave them a lead to defend to take to Merseyside for the second leg of this semi-final in four weeks.

Bergvall swept Dominic Solanke's pass into the net the 86th minute and it might go down as the goal to reignite the Spurs season, but it left Arne Slot and his coaching staff incandescent for two reasons.

One they thought the Swedish teenager should have been sent off because, already on a yellow card, he scythed down Kostas Tsimikas. Two they were not able to get Tsimikas back onto the pitch after treatment and defending without him.

Spurs on the break went long into the space where the left back wasn't and Solanke, exceptional again on the night, dragged Ibrahima Konate out of position, held him off and picked out Bergvall's run.

‘Far from ideal,’ was Slot’s understated reaction, becalmed by the amount of time between the end of the match and his press conference. VAR can only intervene for direct red cards, not yellows or second yellows. 

Postecoglou did not care as celebrations erupted, very different emotions to the last time Liverpool dropped into the neighbourhood and smashed six past his team.

More positive, in fact then in many recent games, with steely defending late on with important saves from new goalkeeper Antonin Kinsky on debut, one of breathtaking brilliance to deny Darwin Nunez in stoppage time, and a superb goal line clearance by Radu Dragusin.

Liverpool summoned a strong finish after sending on Trent Alexander-Arnold, Luis Diaz and Nunez. 

'Significant talent,' noted Postecoglou, whose options on the bench were limited by 10 absentees, but overall Slot's team lacked their usual control and fluency to suffer only a second defeat in 29 games this season.

They were careless and sloppy by their own very high standards this season and should have gone behind earlier, when Pedro Porro fired wide of an open goal when Bergvall hustled Alisson into a mistake on the ball.

Solanke thought he had broken the deadlock, too, but his effort was offside and this time VAR did step in, with the explanation they were promised.

Postecoglou might have cursed at the time. The first round of the competition when it has been used and it came in against his team, but by the end of the night it was Slot who left London scratching his head, wondering why there had been no intervention retracing the move back to the Bergvall tackle, which was not given as a foul by referee Stuart Attwell.

Liverpool though are in the tie. They will feel confident of turning this over at Anfield, but Spurs will hope to be stronger by then, with players fit again.

Kinsky, signed from Slavia Prague for £12.5million on Sunday, was thrown straight into the team after only training twice with his new teammates. 

The first save of the game was made at the other end by Alisson, a brilliant stop, low to his right to deny Dragusin from a corner, but the game came to a long halt because Bentancur had been knocked out as he dived into a header and landed face first into the turf in the Liverpool penalty area.

Thankfully after more than eight minutes of treatment, he was conscious as he disappeared down the tunnel on a stretcher. 

He gave a thumbs-up to Postecoglou and, by half time, was talking in the dressing room.

Liverpool suffered their own injury blow before half time, losing Jarrell Quansah. With Joe Gomez out, Wataru Endo was sent on to partner Van Dijk in the heart of defence. Konate did not come on until the second half.

Kinsky's first real involvements were a couple of panicky moments with the ball at his feet. His first save came from a skidding effort from distance by Cody Gakpo.

It slithered from his grasp and for a split second seemed as if it might be destined for the net before it spun back into the young keeper's hands. 

Kinsky gave his teammates a signal to calm down, as if everything was under control. Perhaps it is a bonus if they have found themselves a lucky goalkeeper.

Chances came and went at both ends. Solanke had turned a low cross from Heung-min Son wide at the near post, Mo Salah fired wide from the edge of the penalty box and Alexis Mac Allister headed straight at Kinsky when unmarked.

Liverpool's changes uncorked the contest. The visitors went forward with more purpose and became more vulnerable to the quick counterattack.

Porro's miss was followed by Solanke's disallowed goal and Nunez went close more than once but the most satisfying factor for Postecoglou will be the way his players dug in and protected the clean sheet.

They have seldom done that in recent weeks and here they did it against the best team in the Premier League. There is work to be done if they are to return to Wembley Stadium, but there are signs of fight once again and this might prove a significant night for Tottenham.