Manchester City overcame an early scare to get their Champions League defence off to a solid start on Tuesday but nine-man Celtic endured a rough night in Rotterdam.
Barcelona cruised past Antwerp and Kylian Mbappe helped Paris-Saint Germain to an opening win on a breathless beginning to the group stage of Europe's top club competition.
Newcastle returned to the high table of European football for the first time in two decades with a battling goalless draw against AC Milan at the San Siro and Lazio grabbed an equaliser deep in injury time to hold Atletico Madrid.
In Manchester, Pep Guardiola's City were stunned when Red Star's Osman Bukari opened the scoring in first half stoppage time.
But Julian Alvarez continued his sparkling early season form by levelling just two minutes after the break.
The Argentine then got some help from Red Star goalkeeper Omri Glazer as he flapped at Alvarez's free-kick to allow the ball to fly into the far corner.
Rodri rounded off a 3-1 win with a composed finish 17 minutes from time.
"If we scored two goals early in the beginning it would've been completely different," said Guardiola, who was frustrated at his side's finishing.
"Having 22 (first-half) shots on goal means you are playing really good. It has to be the responsibility of the people in front to score the goals."
City are next away to RB Leipzig, who share top place in Group E after a 3-1 win at Swiss champions Young Boys.
Mohamed Simaken earned the distinction of scoring the first goal of the group stages with the 2023/24 competition only three minutes old.
The French-born defender's header put Leipzig into a lightning lead in Berne but Elia levelled for the Swiss hosts before Xaver Schlager and Benjamin Sesko wrapped up the win for the Austrian visitors.
In Catalonia Joao Felix struck twice as Barcelona flexed their muscles with a crushing 5-0 win over Royal Antwerp to show their determination to be considered among Europe's elite once again.
After consecutive humiliating group stage eliminations Barcelona are desperate to go deep in this season's competition, last winning it eight years ago.
Felix shone for the Spanish champions on a stroll on a warm night in the Catalan capital, helped on their way by an own goal, with Robert Lewandowski and Gavi also scoring.
That lifted them top of Group H from Porto, 3-1 winners over Shakhtar Donetsk.
Barca's victory followed a 5-0 thrashing of Real Betis on Saturday, leading coach Xavi Hernandez to say: "I think these last two games are the best level we have shown with me as coach -- it's the path to follow."
- 'Almost perfect' -
At Parc des Princes, PSG may have lost Neymar and Lionel Messi over the summer but they held on to Mbappe who set them up for a 2-0 victory over Borussia Dortmund.
The French champions went ahead four minutes after the break when Mbappe scored a spot-kick awarded for a Niklas Suele handball.
Achraf Hakimi added a memorable second, and PSG could have won the Group F encounter by a far more handsome margin in the end.
"It was an almost perfect evening," purred new coach Luis Enrique.
PSG's next date is at Newcastle, whose manager Eddie Howe was proud of his side's dogged return to the competition against seven-time European kings AC Milan.
Howe was the happier of the two managers after taking a point from the clash at the San Siro as his team were mostly on the back foot against last season's losing semi-finalists.
"Definitely pride in result and the performance and the mentality shown," Howe told reporters.
Over in Rotterdam a "bitterly disappointed" Celtic manager Brendan Rodgers was left to rue the "inexperience" of two players sent off in their 2-0 loss to Feyenoord but said the Scottish champions had proved they could be competitive.
Midway through the second half defender Gustaf Lagerbielke was shown a second yellow card after pulling back Brazilian striker Igor Paixao in the box. He was barely down the tunnel when substitute Odin Thiago Holm also saw red for a studs up late challenge.
"Unfortunately for us, we got the two players sent off and it's a difficult level 11 v 11, but 11 v nine is really difficult," said Rodgers who was heartened by the "spirit and mentality" of the nine men left on the pitch.
On Wednesday, record 14-time winners Real Madrid host German debutants Union Berlin, and Bayern Munich with Harry Kane welcome Manchester United who are seeking solace in Europe after a troubling start to the Premier League season.