Jordan Henderson's superb finish gave Liverpool a 3-2 victory from behind over AC Milan in a thrilling opening-night clash in Champions League Group B.
Liverpool burst out of the traps and were 1-0 up early on through Fikayo Tomori's own goal from a Trent Alexander-Arnold cross (9), before Mo Salah saw his penalty saved by Mike Maignan (14), his first miss in 17 for Liverpool.
But Milan produced two goals out of thin air as Ante Rebic's tidy finish (42) and then former Man City man Brahim Diaz's tap home (44) from two similarly blistering breaks stunned Anfield going into half-time.
Salah made up for his penalty miss with a leveller just after the break (48), poking home Divock Origi's clever chip over the defence, and Jordan Henderson completed Liverpool's own comeback with an exquisite half-volley from 20 yards (69) from a cleared corner.
The result, paired with Atletico's 0-0 draw against Porto, puts Liverpool on the front foot in a tricky Group B, with Porto next up away from home on September 28. Jurgen Klopp's side are unbeaten in all competitions this season, and unbeaten in 14 overall.
Liverpool: Alisson (6), Alexander-Arnold (7), Gomez (7), Matip (6), Robertson (8), Fabinho (7), Keita (6), Henderson (8), Salah (7), Origi (7), Jota (6).
Subs: Mane (6), Jones (6), Thiago (6), Oxalde-Chamberlain (NA), Milner (NA)
AC Milan: Maignan (7), Calabria (6), Kjaer (6), Tomori (5), Hernandez (6), Bennacer (5), Kessie (6), Saelemaekers (6), Diaz (6), Leao (6), Rebic (7).
Subs: Giroud (5), Florenzi (5), Tonali (5), Maldini (NA)
Man of the match: Jordan Henderson
How Liverpool came out on top in five-goal classic
It was Anfield's first European night with supporters in attendance since the start of the pandemic, while seven-time winners AC Milan were back in Champions League action for the first time in seven years.
But it was a rude awakening initially for the Italians as Liverpool camped in Milan's defensive third from the first minute; Andrew Robertson and Diogo Jota missed early half-chances, and they took the lead through brilliant combination play between Alexander-Arnold and Salah.
Having played a one-two with Salah around an unsuspecting Rafael Leao, Alexander-Arnold skipped his way into the box on the right, looked to centre, and saw the ball deflect off Tomori and over goalkeeper Maignan for an own goal.
It should have been 2-0 moments later as Liverpool were awarded a penalty for a handball from Ismael Bennacer as he blocked Robertson's cross, but Salah's blasted penalty was saved by Maignan down the middle, before the Milan stopper reacted well to tip away Jota's headed rebound at close range.
Liverpool made four changes to the side that beat Liverpool as Virgil van Dijk was benched alongside Thiago and Sadio Mane, while Harvey Elliott was out injured.
Joe Gomez came in for his first start since November, Divock Origi got his first start since January, while Jordan Henderson and Naby Keita came into midfield.
AC Milan made three changes to the side that beat Lazio on Sunday as Simon Kjaer, Ismael Bennacer and Alexis Saelemakers came in for Alessio Romagnoli, Sandro Tonali and Alessandro Florenzi. Zlatan Ibrahimovic was out injured, while Olivier Giroud was on the bench.
Milan then settled slightly as Liverpool moved to a lower gear, but the chances continued to flow as Joel Matip headed a good opportunity at Maignan, and Salah's snap-shot from the edge of the box was tipped away brilliantly by the busy goalkeeper.
But such is the nature of Champions League football, one moment of quality turned the game on its head. Milan equalised from nowhere as Leao's pass split Matip and Joe Gomez to find Rebic, who wrapped his foot around the ball to finish low past Alisson.
And just 110 seconds later it was 2-1 as Rebic was released again by Leao on the left of the box. This time he squared for Theo Hernandez, whose shot was blocked on the line by Robertson, only for Diaz to tap home again with the Liverpool defender failing to get back to his feet in time.
Liverpool's fans and players went into half-time wondering how their dominance was not reflected in the scoreline.
But they were let off the hook seconds after the restart as Simon Kjaer converted at the back post from a Jordan Henderson error at a corner, only for the offside flag to correctly go up, and it was soon 2-2.
Receiving the ball on the edge of the box from Salah, Origi scooped the ball over the Milan back line for the Egyptian, who composed himself before pushing the ball past Maignan, staying just onside.
AC Milan retreated again, and Liverpool huffed and puffed before getting their third midway through the second half through an unlikely source.
From a half-cleared corner, Henderson's first-time half-volley from the edge of the box was struck superbly, flying into the bottom left corner for only his second Liverpool goal since the end of the 2019/20 season.
The one-goal lead was still fragile as sub Olivier Giroud headed off target, while Alisson just cleared ahead of Milan's front line from a corner, but Liverpool held on.
This wasn't quite Istanbul in 2005, but the victory and comeback was a show of character from a Liverpool side reverting to type following an topsy-turvy 2020/21 season, and a classic European night will contribute heavily to the feeling of normality at Anfield.
Klopp: No Origi interest? Obviously people don't watch enough football!
Jurgen Klopp on BT Sport:
"[Divock] played a beautiful game. People forget how good he is, it's difficult to get into this team.
"In the summer transfer window we all thought there would be a proper offer for him, but obviously people don't watch football enough.
"He's a sensational striker and he did really well today."
Klopp added in his post-match press conference: "He's a great guy. He'll be seen as a legend when he leaves. He could have left in the summer but football is a crazy place and people forgot how good he is. We have to decide the positions. He did nothing wrong."
Opta stats - 2,485 days between Henderson's CL goals
- Liverpool have won their opening home game in seven of their last eight Champions League campaigns (D1), last losing such a match in October 2007 (0-1 against Marseille).
- Under Jüugen Klopp, Liverpool have only lost one of their 13 group stage games in the UEFA Champions League at Anfield (W10 D2) - 0-2 versus Atalanta last season. The Reds have averaged 2.5 goals per home game in the group stage since the German took charge (33 goals).
- Liverpool's Jordan Henderson scored just his 2nd Champions League goal (39th appearance), 2,485 days since his first, against Ludogorets Razgrad in November 2014.
September 28: Porto (A) - kick-off 8pm
October 19: Atletico Madrid (A) - kick-off 8pm
November 3: Atletico Madrid (H) - kick-off 8pm
November 24: Porto (H) - kick-off 8pm
December 7: AC Milan (A) - kick-off 8pm
Liverpool now host Crystal Palace in the Premier League on Saturday at 3pm, while Milan are at Juventus on Sunday evening at 7.45pm in Serie A. Milan's next Champions League group game is at home to Atletico Madrid on September 28 at 8pm.
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