It was another mixed bag for English sides in the Champions League on Matchday 4.

Manchester City and Arsenal secured dominant home victories, while Manchester United and Newcastle each slipped to defeat on their travels.

We take a look at the key talking points from a potentially crucial round of European action.

United on the brink

United's chances of qualification for the knockout phase suffered a significant blow in Copenhagen as they were beaten 4-3 to leave them bottom of Group A.

Erik ten Hag's outfit looked well on the way to a morale-boosting victory after Rasmus Hojlund's early brace against his old side.

But Marcus Rashford's 42nd-minute red card changed the course of the game, with Copenhagen going in at half-time level thanks to efforts from Mohamed Elyounoussi and Diogo Goncalves.

Bruno Fernandes put 10-man United back ahead from the penalty spot, only for the Red Devils to be left broken hearted by Lukas Lerger and Roony Bardghji's late strikes.

Newcastle nightmare

Newcastle's Champions League hopes are hanging in the balance after being defeated 2-0 by Borussia Dortmund.

The German outfit made it back-to-back victories over the Magpies, with Niclas Fullkrug and Julian Brandt grabbing the goals at Signal Iduna Park.

Eddie Howe's side enjoyed 55% of the possession and mustered five shots on target but could not find a way past Gregor Kobel in the Dortmund goal.

Newcastle sit bottom of Group F on four points and will have to avoid defeat at Paris Saint-Germain in their next match to stand a chance of qualifying.

Harry at it again

Harry Kane continued his superb start to life at Bayern Munich by netting both goals in the 2-1 win over Galatasaray.

The England captain opened the scoring in the 80th minute and followed that up with another strike six minutes later — his 19th in all competitions this season.

Cedric Bakambu's stoppage-time effort was merely a consolation as Bayern stretched their unbeaten run in the Champions League group stage to 38 games.

Kane sits joint-second in the competition's Golden Boot race with four goals — Hojlund and Alvaro Morata lead the way on five apiece.

All Guns blazing

Arsenal are on the brink of reaching the Champions League knockout stage after a dominant 2-0 win over Sevilla.

Goals from Leandro Trossard and Bukayo Saka secured a deserved victory at the Emirates.

Saka unfortunately hobbled off the pitch late in the second half due to an awkward landing, although Mikel Arteta did not seem too concerned by the injury after the game.

The Arsenal boss said: "He [Saka] will have some discomfort but hopefully, I want to assume that he will be OK."

City cruising

Champions City made it four victories in a row as they defeated Young Boys 3-0 at the Etihad.

A brace from Erling Haaland steered Pep Guardiola's side to three more points, the Norwegian taking his Champions League goal tally to 39 in just 34 appearances.

Haaland's second strike was a superb long-range effort, one which surprised his manager.

Guardiola said: "Yes [Haaland still surprises me], because normally he scores goals in the six-yard, eight-yard box and by the penalty spot. 

"But he has this talent, it's not the first time he has done it."