Dortmund score 7, while Man City Barcelona and Arsenal all win

Associated Press: London Karim Adeyemi starred as Borussia Dortmund ran riot against Celtic while Barcelona and Manchester City claimed their first wins in the restructured Champions League. Adeyemi scored a firsthalf hat trick as Dortmund routed Celtic 7-1 at home. It was the second big win from a German team in the competition after Bayern Munich's 9-2 bashing of Dinamo Zagreb in the first matchday. Robert Lewandowski got Barcelona off the mark as the Spanish giant eased to a 5-0 home win over Swiss team Young Boys, while his former teammate Ilkay Gündogan got City off to a 4-0 win at Slovan Bratislava.

Erling Haaland scored his 42nd goal in his 41st Champions League game. City was held 0-0 by Inter Milan in their opening game, while Barca responded to its 2-1 loss at Monaco, the team's first defeat under new coach Hansi Flick. Mikel Arteta's Arsenal outclassed his former team Paris Saint-Germain in a 2-0 win with Kai Havertz and Bukayo Saka scoring in the first half for the Gunners. PSG coach Luis Enrique's gamble on leaving Ousmane Dembélé out did not pay off.

Arteta enjoyed a successful 18-month loan spell at PSG while still he was still a teenager at Barcelona. Dortmund fans cry foul Though the Dortmund team appears to have adapted to the new competition format very well — last season's beaten finalist has 10 goals from two games after starting with a 3-0 win over Club Brugge — its fans made their opposition to the reforms clear with a huge tifo slamming UEFA. This season UEFA changed the structure of Europe's premier competition to add four more teams. The group stage was scrapped for a league system with each of the now 36 participating teams playing eight opponents once in a first phase of the competition.