Cape Town - Carlo Ancelotti said his Bayern Munich side struggled to contain Arsenal in their Champions League last-16 second leg until the pivotal moment in the match when Laurent Koscielny conceded a penalty and was sent off.
The Gunners' defender was initially shown a yellow card for the challenge on Robert Lewandowski in the 53rd minute - with Arsenal in a 1-0 lead thanks to Theo Walcott - before the line official suggested the referee had got the decision, leading the official to promptly produce a red card.
The Polish strike duly converted his kick, leading to a deluge of Bayern goals as Arjen Robben and Douglas Costa scored a goal each, and Arturo Vidal bagged a brace.
The match ended 5-1 and 10-2 to the German giants on aggregate.
After the match, Ancelotti admitted his side were up against it, until the spot-kick.
He told the club's official website: "It was a tough match. We had problems in defence until the penalty. They applied pressure as we had expected, but we should have controlled the game better.
"We weren't as good as normal in possession. But it happens. It's hard to stay focused if you're 5-1 up. We'd said we wanted to stick to our game plan, but it's not easy when you're so clearly in front."
Karl-Heinz Rummenigge added: "There are no easy matches in the Champions League, especially away from home. Arsenal did a good job in the first half. They were closer to doubling their lead than we were to an equaliser.
"It was only after the penalty that the tide turned, and then we won deservedly."
And Bayern goalkeeper Manuel Neuer concluded: "Apart from the first ten minutes things didn't go as planned at first. We didn't want to concede a goal, but then we scored five."