Arsenal’s Kai Havertz maintained his impressive start to the season with the opening goal in a 2-0 home victory against Paris St Germain which kick-started the London club’s Champions League campaign while Dortmund hit seven past Celtic with Dortmund’s Adeyemi netting a first half hatrick.

After drawing away to Italian side Atalanta in their opening game the onus was on Mikel Arteta’s side to deliver a home win against last year’s semi-finalists and they delivered.

German forward Havertz headed his side in front after 20 minutes with his fifth goal of the season and 15 minutes later Bukayo Saka’s free kick somehow found its way into the PSG net to put the hosts in complete control.

PSG, who won their opening game against Girona, struck the woodwork in each half and played with more urgency after the interval but could have few complaints about the outcome.

Champions League: Wednesday’s fixtures

Girona v Feyenoord (19.45)
Shakhtar Donetsk v Atalanta (19.45)
Aston Villa v Bayern München
Benfica v Atlético Madrid
Dinamo Zagreb v Monaco
Lille v Real Madrid
Liverpool v Bologna
RB Leipzig v Juventus
Sturm Graz v Club Brugge

All games start at 22.00 unless otherwise stated

Victory propelled Arsenal into the top eight of the new 36-team league phase with their next match at home to Shakhtar Donetsk after the international break. PSG will seek to bounce back in their next match at home to PSV Eindhoven.

Such is the confidence sweeping through Arsenal at the moment that a home game against seasoned European opposition managed by Luis Enrique held no fears.

They almost made the perfect start in route-one fashion as a long clearance by keeper David Raya skimmed off the wet turf and Gabriel Martinelli almost nicked it past Gianluigi Donnarumma.

Arsenal took the lead in the 20th minute as Trossard was allowed too much time on the left and his lofted ball was perfect for the late run of Havertz who nodded past the out-of-position Donnarumma into an empty net.

Nuno Mendes struck a left-footed shot against the post as PSG responded but Arsenal soon doubled their lead.

Havertz’s goal extended PSG’s run without a clean sheet away from home in the Champions League to 20 — a sorry sequence starting four years ago.

And the way they conceded again in the 35th would not have looked out of place on a local park pitch.

Saka curled a free kick from the right into a crowded penalty area and the ball evaded everyone and left Donnarumma red-faced as it nestled into the net.

PSG’s hopes of mounting a second-half comeback were hardly helped by Luis Enrique’s decision to omit forward Ousmane Dembele from the squad for disciplinary reasons.

Instead it was Arsenal who looked like extending their lead with Martinelli’s volley well saved by Donnarumma and Havertz heading weakly at the keeper.

Arsenal’s energy levels began to drop and Arteta gave a substitute appearance to new signing Mikel Merino, his first appearance for his new club.

PSG pressed hard late on and Joao Neves’s close-range flick from a corner was turned against the crossbar by Raya who moments later did well to block Lee Kang-in’s shot.

But Arsenal managed the game well as they sent out a statement of European intent.

Borussia Dortmund’s Karim Adeyemi scored a first-half hat-trick as last season’s losing finalists hammered Celtic 7-1 in the Champions League on Tuesday with five goals in the opening 42 minutes.

The humbling scoreline sent Dortmund top of the 36-team Champions League standings, with two wins from two matches and a goal difference of nine, while Celtic plunged from third to 19th.

“A sore one, for sure. We were punished with every mistake we made. Before we knew it, we were 5-1 down. A sobering night,” Celtic captain Callum McGregor told TNT Sports.

The 80,000 crowd started the celebrations early at the Westfalenstadion, with captain Emre Can scoring from the spot in the seventh minute after Celtic goalkeeper Kasper Schmeichel up-ended Jamie Gittens and was booked.

Celtic momentarily hushed the deafening Yellow Wall two minutes later when Daizen Maeda bundled in a cross from Arne Engels but Adeyemi restored the lead with a shot deflected in off Auston Trusty in the 11th.

The Germany winger made it 3-1 in the 29th when he lashed the ball into the top corner past the diving Schmeichel, then won a 39th minute penalty for Serhou Guirassy to tuck away before completing his hat-trick three minutes later.

Adeyemi was substituted with an injury shortly after the break, the 22-year-old applauding fans as he left.

Guirassy grabbed his second of the night in the 66th and second-half substitute Felix Nmecha completed the rout in the 79th, with Celtic having Schmeichel to thank for keeping the sobering scoreline to seven.

“It was a great night. Almost the perfect night for us. Everything went right. It’s great to get such a big win,” said Can. “We’ve made a really good start, but there’s still a long way to go.”

CELTIC SHREDDED

The halftime shredding rewound Celtic’s goal difference to zero after their 5-1 thrashing of debutants Slovan Bratislava in their opening match last month, and it only got worse.

Guirassi’s second came after a poor clearance by Alistair Johnson as Celtic, who arrived with some confidence of getting a good result, paid the price for slack passing and scant possession.

Adeyemi was the first Dortmund player to score a first-half hat-trick in Europe since 2002 and his achievement left the 4,000 travelling Celtic fans shell-shocked as the speedy hosts ripped their side apart.

“We scored seven goals, so it was a really good night. We can reach the final again if we keep playing like this,” he said afterwards.

Both teams had started unchanged from weekend domestic league games with Celtic the leaders in Scotland and Dortmund, 3-0 winners at Belgian side Club Brugge in their European opener, fifth in the Bundesliga.

“The quick goal killed us and rattled us a little bit. When you give good players time on the ball, they will kill you. And that’s what they did,” said McGregor.

Dortmund coach Nuri Sahin said his team set the bar high.

“We were always looking to go forward, and we’re difficult to beat when we play like that. I was incredibly pleased with the amount of effort we put in,” he said.

Dortmund’s next game is at Real Madrid on Oct. 22, a repeat of last year’s Wembley final, while Celtic play last year’s Europa League winners Atalanta in Italy on Oct. 23.

Tuesday’s Champions League results:

Salzburg (0) 0 Brest (1) 4
Stuttgart (1) 1 Sparta Praha (1) 1
Barcelona (3) 5 Young Boys (0) 0
Bayer Leverkusen (0) 1 Milan (0) 0
Borussia Dortmund (5) 7 Celtic (1) 1
Internazionale (1) 4 Crvena Zvezda (0) 0
PSV (1) 1 Sporting CP (0) 1
Slovan Bratislava (0) 0 Manchester City (2) 4
Arsenal (2) 2 PSG (0) 0