Watch: Adeyemi's hat-trick helps BVB hand Celtic brutal reality check

Borussia Dortmund scored a touchdown against Celtic on Tuesday. (And converted the extra point)

The German club claimed a dominant 7-1 win in their Champions League encounter, with Karim Adeyemi scoring a first-half hat-trick.

The Dortmund forward showed off his finishing ability with tallies in the 11th, 29th, and 42nd minutes as Dortmund built a huge 5-1 lead going into the halftime interval. All three goals were impressive, but his second of the game, a left-footed rocket from a tight angle, was the pick of the bunch.

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However, the young German's match ended on a dour note, as he was substituted in the second half after picking up an apparent leg injury.

Emre Can, Serhou Guirassy, and Felix Nmecha also found the net for Dortmund, who remained perfect in the league phase of this season's competition after two matches.

The win matched Dortmund's biggest-ever Champions League victory.

"There's no such thing as a perfect game, but it was very, very good," Can said. "This has to be the standard we aim to set."

Dortmund resume their continental campaign later in October with a trip to Real Madrid. The Matchday 3 contest will be a rematch of last season's tournament final, which the Spanish giants won.

Celtic, meanwhile, have to regroup after the harsh reality check.

"When you give good players time on the ball, they will kill you. And that's what they did," Celtic captain Callum McGregor explained.