Harry Kane scored a second-half penalty as Bayern Munich claimed a 4-3 victory over Manchester United in their Champions League group-stage opener on Wednesday.

It was a fourth defeat in just six matches for Erik ten Hag's floundering United in all competitions this season as they failed to bounce back from last weekend's embarrassing 3-1 home loss to Brighton in the Premier League.

Bayern took control when visiting goalkeeper Andre Onana let Leroy Sane's weak shot roll into the net in the 28th minute before Serge Gnabry swept home a second.

Rasmus Hojlund pulled one back before Kane drilled in a penalty early in the second half.

Casemiro's late effort briefly gave United hope of an unlikely comeback against the run of play, but Bayern substitute Mathys Tel smashed home a fourth for the hosts in added time.

Brazilian Casemiro nodded in another consolation goal for United from the last attack of the match.

Six-time European champions Bayern moved top of the early Group A table after Wednesday's earlier 2-2 draw between Galatasaray and FC Copenhagen in Istanbul.