Liverpool captain Jordan Henderson has struck a rare Champions League goal to earn his side a 3-2 victory over AC Milan in a rip-roaring Group B opener at a rocking Anfield.
An own goal from Fikayo Tomori and a saved Mohamed Salah penalty did not tell the whole story as Liverpool dominated - only to be struck by two goals in less than two minutes just before the break as Ante Rebic and Brahim Diaz shocked Anfield.
Salah would make amends for his missed spot-kick as he stayed onside to turn home a Divock Origi pass to equalise before Henderson's effort settled the contest.
Reds boss Jurgen Klopp said the game was everything he had hoped for, with a full crowd for a European fixture for the first time since March 2020.
"Very exciting and very entertaining with 10-15 minutes where we lost a little bit of the plot or whatever and were not compact any more," he said.
"We got carried away with our own football and complicated matters. They scored two goals and then we played again good football and scored two wonderful goals."
The win puts Liverpool top of Group B as Atletico Madrid and Porto played out a goalless draw in Spain - with Chancel Mbemba was sent off late on for the visitors.
Jack Grealish scored on his Champions League debut as Manchester City were involved in a high-scoring thriller as last season's beaten finalists eventually overcame 10-man RB Leipzig.
Christopher Nkunku scored a hat-trick for the visitors but City were always slightly on top and ran out 6-3 winners.
Nathan Ake had put the hosts ahead before Nordi Mukiele's own goal doubled the lead.
Riyad Mahrez's penalty restored a two-goal lead after Nkunku's first of the night and he would strike again before Grealish then finished well.
Nkunku completed his hat-trick to once again get the visitors within one goal before Pep Guardiola's men finally accelerated clear through Joao Cancelo and Gabriel Jesus.
"It just shows you anything can happen in the Champions League," Grealish said. "That's why it's such a wonderful competition.
Paris Saint-Germain started with Lionel Messi, Neymar and Kylian Mbappe in attack but had to settle for a point in a 1-1 draw at Club Brugge.
Mbappe provided the assist for Ander Herrera to score his maiden Champions League goal for the away side, who saw Hans Vanaken level.
"I didn't really have much work to do," Brugge goalkeeper Simon Mignolet said.
Meanwhile, England midfielder Jude Bellingham was the star of the show as Borussia Dortmund began their Group C campaign with a 2-1 win at Besiktas.
The 18-year-old's smart control and finish gave Dortmund the lead before he set up Erling Haaland to double the visitors' advantage in first-half stoppage time, while Javi Montero headed in a last-gasp consolation for Besiktas.
Sebastien Haller scored four goals in his Champions League debut as Ajax thrashed Sporting Lisbon 5-1 in Portugal.
Haller had the visitors two up inside the opening 10 minutes before Paulinho pulled one back.
Steven Berghuis re-established the two-goal cushion as Haller then completed his hat-trick and added a fourth just after the hour.
Real Madrid secured a late 1-0 win over Group D heavyweights Inter Milan as Rodrygo struck with a minute to go at the San Siro, while Sheriff Tiraspol were victorious on their Champions League group stage debut - Adama Traore and Momo Yansane scoring either side of half-time for a 2-0 win over Shakhtar Donetsk.
Australian Associated Press