CNN  — 

Few gave Liverpool a chance ahead of its Champions League semifinal against Barcelona on Tuesday.

Blown away by Lionel Messi et al in the first-leg tie as Barcelona won 3-0 at the Camp Nou, Liverpool needed four goals to reach the final in Madrid on June 1.

Liverpool had also been weakened by the absence of a trio of key players through injury – Mo Salah, Roberto Firmino and Naby Keita. That meant manager Jurgen Klopp turned to players like Divock Origi and Xherdan Shaqiri, who for much of the season have been confined to the substitutes bench.

Perhaps that’s the greatest tribute to Klopp’s man management skills, because both Origi and Shaqiri were vital to Liverpool’s 4-0 win. Origi scored twice, while Shaqiri set up Gini Wijnaldum for Liverpool’s third goal.

“We played against maybe the best team in world,” Klopp told BT Sport. “Winning is difficult, but winning with a clean sheet, I don’t know how they did it.

“Divock and Shaq didn’t play a lot. Putting a performance in like that, it was so important. It shows what’s possible in football. It’s so nice. It’s really nice.

“I saw James Milner crying on the pitch after the game. It means so much to all of us.”

But how does Liverpool’s remarkable victory rank against the competition’s greatest and most memorable matches?

Here’s a look back at some of the best.

Obviously, the list is not exhaustive, and there have been far too many great games to include them all. Still, let us know which ones we missed out on by leaving a comment on our Facebook page.

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Jordan Henderson played a key part in Liverpool's first goal.

Manchester City 4-3 Tottenham Hotspur

Five goals in the first half. Seven by full-time. And another, potentially decisive strike, dramatically ruled out by the video assistant referee (VAR) in injury time.

Last month’s Champions League quarterfinal second leg between Manchester City and Tottenham Hotspur had absolutely everything.

With Spurs holding a slender 1-0 advantage from the first leg, the lead and momentum shifted multiple times at the Etihad stadium. When the dust settled, it was the London club that was victorious, triumphing on away goals and ending City’s dreams of an unprecedented trophy quadruple.

One English newspaper described the encounter as an “inconceivable classic” while others said it was “extraordinary” and “unbelievable.”

Liverpool 3-3 AC Milan, 2005 final

Arguably the greatest European final of all time. Liverpool looked to be on the end of a drubbing after an early goal from Paolo Maldini and a brace from Hernan Crespo, the second of which saw the Argentine latch onto one a sublime through ball from the Brazilian international Kaka, gave pre-match favorites Milan a 3-0 halftime lead.

But a rousing 15 minutes at the start of the second period saw Liverpool’s captain-fantastic, Steven Gerrard pull one back before Vladimir Smicer and Xabi Alonso leveled matters.

Extra time couldn’t separate the sides so penalties were required. Serginho and Andrea Pirlo missed for Milan before Liverpool goalkeeper Jerzy Dudek saved the decisive kick from Andrei Shevchenko to give Liverpool an unlikely and remarkable win.

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Deportivo La Coruna 4-0 AC Milan, 2004 quarterfinal

Sorry Milan fans, here’s another match you’d probably rather forget. Leading Deportivo La Coruna 4-1 from the quarterfinal first leg at the San Siro, Milan traveled to northwestern Spain as firm favorites to see out the tie.

But Depor had other ideas as goals from Walter Pandiani, Juan Carlos Valeron and Albert Luque put them ahead on aggregate using the away goals rule before halftime. Fran added a fourth in the second period to secure victory.

Depor’s surprise comeback was one of a number of upsets in the 2003-04 Champions League that saw an FC Porto side, coached by a young Jose Mourinho, win an unlikely final against Monaco.

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Manchester United 4-3 Real Madrid, quarterfinal 2003

Manchester United may have won this game, but it was all about Real Madrid and the devastating finishing of Ronaldo.

Real had won the first leg 3-1 in the Spanish capital, and a hat-trick from the Brazilian superstar meant Los Blancos would claim a 6-5 aggregate victory across the tie.

Ronaldo’s third goal, in particular, was a standout as he crashed an arrowing drive beyond Fabien Barthez in the United goal.

Although United battled ably and the momentum shifted a number of times across the match, which also featured a stunning David Beckham free-kick, it was one Real and Ronaldo firmly deserved to win

United fans even gave “O Fenomeno” a standing ovation as he was substituted late in the game.

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Monaco 8-3 Deportivo la Coruna, 2004 group stages

At the time, this was the highest scoring standalone Champions League match ever – a goalfest for the ages.

Croatian striker, Dado Prso, scored four while Jerome Rothen, Ludovic Giuly, Jaroslav Plasic and Edouard Cisse were also on target as Monaco cut loose.

Although the Spanish side was humbled, it would go on to reach the semifinals after a dramatic comeback against Milan (see above) before succumbing to eventual winners Porto in the semifinals.

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Ajax 5-2 Bayern Munich, 1995 semifinal

After a goalless first leg in Munich, few expected this high-stakes affair to prove so entertaining.

The flying Finn, Jari Litmanen, put Ajax on its way but Bayern promptly leveled through Marcel Witeczek. Unperturbed, the Dutch team took control of the game before halftime with strikes from Finidi George and Ronald De Boer. Litmanen added another shortly after the break.

Bayern battled to get back into the game and did pull one back through a Mehmet Scholl penalty. But Marc Overmars extended the lead for Louis van Gaal’s young Ajax side with a late strike to make it 5-2.

Ajax would go on to defeat Milan in the final in Vienna.

VIENNA, AUSTRIA - MAY 24:  AJAX AMSTERDAM - AC MAILAND 1:0, Wien; Champions League Finale 1995 in Wien; AJAX AMSTERDAM CHAMPIONS LEAGUE SIEGER 1995 mit Pokal  (Photo by Alexander Hassenstein/Bongarts/Getty Images)
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Barcelona 6-1 Paris Saint Germain, 2017 round of 16

Barcelona and Messi has achieved some magical things over the last 15 years. But this is right up there with the best of them. After a 4-0 pummelling in the Paris first leg, the Catalan club required all of their legendary firepower to overcome a strong PSG in the return.

Luis Suarez, a Layvin Kurzawa own goal and a Messi penalty put Barça 3-0 up and the comeback looked very much on. But Edinson Cavani scored what seemed like the vital away goal for PSG just after the hour mark.

That meant Barcelona needed another three goals to go through. As the clocked ticked down, such a scenario looked increasingly unlikely with PSG spurning a number of good chances. But Neymar gave Barça feint hope with a 88th minute free-kick. Two minutes later a second penalty was awarded and duly dispatched by the Brazilian.

The momentum was heading only one way, but time was running out. Step forward Sergi Roberto, an unlikely hero, who stretched to score from Neymar’s dinked cross and send the Nou Camp into raptures.

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SEVILLE, SPAIN - MARCH 17: Lionel Messi of FC Barcelona reacts during the La Liga match between Real Betis Balompie and FC Barcelona at Estadio Benito Villamarin on March 17, 2019 in Seville, Spain. (Photo by Aitor Alcalde/Getty Images)
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Prior to this game there had been 213 European games since 1955 where the first leg of a tie had finished 4-0. Such a deficit had never been overturned – until the Barcelona of Messi, Neymar and Suarez faced down PSG.