Dortmund hammer Celtic 7-1 after Adeyemi first-half hat-trick

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.

"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 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.

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.

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.