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 first-half 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 giants eased to a 5-0 home win over Swiss team Young Boys, while his former teammate Ilkay Gundogan got City off to a 4-0 win at Slovan Bratislava. Erling Haaland scored his 42nd goal in his 41st Champions League game.

City were held 0-0 by Inter Milan in their opening game, while Barca responded to their 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 Dembele out did not pay off.

Arteta enjoyed a successful 18-month loan spell at PSG while still he was still a teenager at Barcelona.

Fans cry foul

Though Dortmund appear to have adapted to the new competition format very well — last season’s beaten finalists have 10 goals from two games after starting with a 3-0 win over Club Brugge — their fans made their opposition to the reforms clear with a huge tifo slamming Uefa.

The supporters displayed the words “Uefa mafia” behind one of the goals above a banner saying “You don’t care about the sport — all you care about is money!” Another banner above showed a website link making clear the banners referred to Champions League reforms.

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.

Uefa claimed the changes would ensure more evenly matched games, but Tuesday’s results — the big wins for Barca, City and Dortmund — appear to belie that claim.

There were more big wins on Tuesday with Inter Milan defeating Red Star Belgrade 4-0, and tournament debutant Brest routing Salzburg 4-0 away for its second win in as many games in Europe’s premier competition.

Iran forward Mehdi Taremi struck a penalty past Israel and Red Star goalkeeper Omri Glazer and set up two more goals for Inter hours after his country launched a barrage of missiles at Israel.

Senegalese forward Abdallah Sima netted twice for Brest to take his tally to three goals in two games after he scored in the French team’s tournament-opening 2-1 win over Austrian champion Sturm Graz. Also on Tuesday, Bayer Leverkusen defeated AC Milan 1-0 in Germany thanks a well-worked move finished by Victor Boniface.

Daniel Bragança scored late to earn Sporting Lisbon a 1-1 draw at PSV Eindhoven.

Kaan Kairinen’s brilliant free-kick was enough for Prague to draw 1-1 at Stuttgart. Stuttgart fans displayed a huge choreography saying “Back in Europe” behind one of the goals. It was the German team’s first Champions League match at home since a 1-1 draw with Barcelona in February 2010.

Middle East sub-plot

Taremi scored his first goal for Inter as he struck a penalty past Israel and Red Star Belgrade goalkeeper Omri Glazer.

Taremi, who joined from Porto in the offseason, played a crucial role in Inter’s 4-0 victory over Red Star by also setting up two of his team’s other goals. Shortly before kick-off at San Siro, Iran fired at least 180 missiles into Israel — the latest in a series of escalating attacks in a yearslong conflict between Israel and Iran and its Arab allies that threatens to push the Middle East closer toward a regionwide war.

The 32-year-old Taremi was not asked about the situation back in his homeland when he was interviewed by Italian television, which focused on his first goal for the Nerazzurri.

“I am glad to score tonight (Tuesday), to play good, thanks to my teammates. It was great,” Taremi said.

“I am so excited, it took a while for me to score, but I always tried to do my best in training, I fought for this moment and managed to get the goal tonight.”

Also before Tuesday’s game at Dortmund, Celtic fans flew Palestinian and Lebanese flags.

Frenkie de Jong made his long-awaited return to Barcelona after being sidelined for nearly five months because of an ankle injury.

The Dutch midfielder replaced Lamine Yamal in the 75th minute of Barcelona’s 5-0 rout of Young Boys.

With inputs from AP/PTI, Reuters