Paris Saint-Germain superstars Lionel Messi, Neymar and Kylian Mbappe were fielded together for the first time on Wednesday but none of them scored in a 1-1 Champions League draw at Club Brugge.
Ander Herrera put PSG ahead but the Belgian hosts showed no fear and got a deserved equalizer from captain Hans Vanaken.
Last season's runners-up Manchester City beat 10-man RB Leipzig 6-3 while Liverpool defeated AC Milan 3-2 in another turbulent game in which Mohamed Salah missed a penalty and the hosts trailed 2-1 at the break.
Leipzig's Christopher Nkunku scored a hat-trick at the Etihad but was upstaged on the night by Sebastien Haller who netted four in Ajax' 5-1 triumph at Sporting.
Messi, Neymar and Mbappe meanwhile came up empty-handed as they were fielded together for the first time since Messi's summer arrival from Barcelona.
Mbappe set up Herrera's opener in the 15th but Vanaken's deflected effort in the 27th saw the courageous Belgians level.
Playing in his 150th Champions League match, Messi curled against the crossbar but PSG goalkeeper Keylor Navas then had to come to the rescue with big saves against Vanaken and Charles de Ketelaere before Mbappe limped off injured.
"It's the Champions League, we came up against a very good Brugge side even if we didn't play our football," PSG defender Presnel Kimpembe said.
"You have to respect everyone, even if we know that on paper we have a great side. You have to show it on the pitch."
In the other Group A game, newely-signed defender Nathan Ake headed City ahead and an own goal from Leipzig's Nordi Moukiele made it 2-0 in the 28th.
Nkunku pulled one back on three occiasions but Riyad Mahrez' penalty in the 45th, Jack Grealish's curler in the 56th and Joao Cancela always swiftly restored City's two goal advantage.
Former City player Angelino was sent off late for Leipzig and Gabriel Jesus completed the half dozen in the 85th.
Liverpool were all over Milan at Anfield in Group B, with Fikayo Tomori deflecting Trent Alexander-Arnold's shot after a one-two with Salah in the 9th from a tight right angle to put the hosts ahead.
Salah then had a penalty saved by goalkeeper Mike Maignan and the Reds wasted many chances which backfired shortly before the break when Ante Rebic and Brahim Diaz turned around matters out of the blue.
Milan had a third disallowed for offside seconds after the restart before Liverpool hit back. Salah made it 2-2 off a chipped pass from Divock Origi and captain Jordan Henderson fired the 3-2 winner in the 64th from the edge of the area.
"When you play in this tournament it is against good teams. We need to be smarter. Really tough but we managed to come out second half, play our football and enjoy it again," Liverpool's defender Andy Robertson told BT Sport.
Atletico Madrid and Porto drew 0-0 in the other game.
Four-time winners Ajax are the early Group C leader with Haller scoring the first two of his four goals in the opening nine minutes.
Borussia Dortmund are second after England teenager Jude Bellingham opened the scoring and set up Erling Haaland for the other for a 2-1 victory at Besiktas. Haaland now has 21 goals in 17 games in the elite event.
Group D started with record winners Real Madrid winning late from Rodrigo at Inter Milan. Moldova debutants Sheriff Tiraspol stunned Shakhtar Donetsk 2-0 from Adama Traore's volley and Momo Yansane.