It was a decision referee Michael Oliver had to make.

Despite the protests and bickering in the final minutes of Wednesday’s heated Champions League quarter-final second leg at the Santiago Bernabeu, the Englishman had no choice but to award a penalty.

Deep into second-half stoppage time, Medhi Benatia knocked Lucas Vazquez down as he tried to win a crucial ball. The Real Madrid substitute had a clear look at goal before the Juventus defender’s intervention. Already on a yellow card, Benatia could and probably should have been sent off for denying a clear goalscoring opportunity.

Although the decision was heavily debated, there was more than enough evidence to call a foul. The Moroccan international wrapped his leg around Vazquez in an attempt to clear, an infraction that would have been called anywhere else on the pitch. Benatia had done himself no favours by lunging into a tackle minutes earlier to catch the attention of Oliver, and the fact he challenged Vazquez from behind only amplified the risk.

The Bianconeri, however, could have avoided the sequence altogether.

It all started when Benatia drifted out to the right, having to cover for the casual Stephan Lichtsteiner as Isco infiltrated space down the wing. Benatia then found himself out of position, and with the play switching sides, was unable to track back in time to make a legitimate clearance.

(Courtesy: BT Sport)

Juventus’ attempt at an offside trap also left Vazquez all alone. Unbeknownst to his teammates holding a high line, Alex Sandro stayed behind, playing Cristiano Ronaldo onside and allowing the Portuguese superstar to nod a free ball into the box.

(Courtesy: BT Sport)

Juventus had done so well to bring itself back into the tie. It was an inverted image of the first leg, with Juventus making the most of its limited opportunities this time around. Scoring three goals is no easy feat in such hostile territory, and yet all the hard work was undone in the closing stages as the Bianconeri let the result slip away with slack defending. They had played without the ball for the majority of the contest and conceded some genuine scoring chances to Madrid, including a header that crashed off the crossbar. Gianluigi Buffon made some good saves, but the visitor’s resistance simply couldn’t handle the additional three minutes of stoppage time.

Related – Buffon: Referee ‘has a trashcan in place of a heart’

The subsequent fallout was a sad sight. Buffon couldn’t help himself. A World Cup winner and multiple Italian champion, the 40-year-old was sent off – his first red card in 117 appearances in the competition. The moment was so tense that a visceral reaction was inevitable.

“It’s unbelievable that our captain isn’t allowed to speak to the referee,” Benatia said afterward. “The red card was very harsh.”

Not that Buffon – or anyone else – would have saved the following kick. Ronaldo was forced to stew for several minutes, and yet still converted coolly into the top corner.

It was an unfortunate way to end a riveting match, but Oliver should be commended for not allowing the context of the tie, then 3-3 on aggregate after the remarkable comeback, to influence his decision.

Buffon’s dismissal can be debated – no one knows exactly what he said and whether he touched the official – but the penalty was just.

The story in the first months of the season was more about Liverpool’s frailties than its attacking virtues. The Reds had conceded 16 goals through their first nine league matches – more than any other Liverpool team had since 1964-65. Dejan Lovren, substituted just 31 minutes into a 4-1 trouncing at Tottenham, was an accident waiting to happen.

Then there was the setback against Swansea City – a 1-0 defeat despite 71.8 percent possession – and West Bromwich Albion days later in the FA Cup. Midfield battles were lost and free headers were conceded in the penalty area. Jurgen Klopp was stuck answering questions about his defensive record, and whether he was abandoning the fundamentals of the game.

But the narrative has changed. Three consecutive wins over Manchester City – including two in the Champions League quarter-finals – show how far Liverpool has come. Progress to the semi-finals certainly required goals from Mohamed Salah, Roberto Firmino, and Sadio Mane, but also a great deal of resilience and organisation at the back.

The giveaway that led to Gabriel Jesus’ second-minute opener on Tuesday was the kind of fatal error that would have killed previous iterations of this Liverpool side – “a wonderful goal that we served them on a plate,” Klopp said – but the resolve was there to snatch a 2-1 victory.

After a difficult first half, the visitor emerged as a more compact unit. Lovren and Virgil van Dijk commanded the penalty area, and it became more difficult for City to fashion genuine scoring chances. City may have had 20 shots, but Loris Karius was drawn into just three saves, which should be read as a compliment to his defenders. Lovren and Van Dijk, who combined for 21 clearances in the reverse leg, made sure that the majority of the shots came from a safer distance.

Liverpool was also economical with the ball, doing as much as it could with the little possession that it had. It cut right through the middle to set up Salah’s equaliser and jumped on a mistake by Nicolas Otamendi as Firmino scored the winner. Liverpool was more difficult to push off the ball in the second half, and against City’s press, it had to be.

Liverpool has had success on the counter because its defence has done a good enough job soaking up pressure and limiting the damage. Managing 35 percent possession or less in the three wins against Pep Guardiola’s men, the Merseyside outfit had no choice but to hassle and harry such a vaunted opposition. Leaving any more free time on the ball would’ve been suicidal. So, Liverpool kept a higher line in the second half Tuesday, forcing City to make tougher decisions on the ball.

Despite his reputation as a gunslinger, Klopp’s always been attentive to the defensive side of the game. His upbringing as a footballer in Germany’s lower tiers involved an intimate understanding of tactics. He became a disciple of former Mainz manager Wolfgang Frank, one of the forefathers of Gegenpressing, and adored the tireless training regimens of AC Milan visionary Arrigo Sacchi.

Frank’s philosophy of defending narrowly, as Raphael Honigstein described in his book “Bring the Noise: The Jurgen Klopp Story,” had an enormous effect on Klopp. As one of the defenders in Frank’s back four at Mainz, the German realised that “our system made us beat teams that had better players.” Klopp learned that teams that use space well can achieve results “independent of our talent.”

When pestered about his defensive credentials earlier this season, Klopp insisted he could “write a book about which space we have to defend, why, when, and where you have to be, when you have to push up. But you have to do it.”

On the basis of Tuesday’s evidence, Klopp’s plan is finally working.