Newcastle manager Eddie Howe said he would not use his side's mounting injury list as an excuse for a 2-0 loss at Borussia Dortmund on Tuesday.
Newcastle, who lost 1-0 two weeks ago to Dortmund in England, went down to a fired up home side who were thumped 4-0 by rivals Bayern Munich on Saturday.
Niclas Fuellkrug opened the scoring midway through the first half, his first Champions League goal, before the impressive Julian Brandt sealed the game with a strike 11 minutes from time.
Howe's side are missing several first team players through injury and suspension, which the manager said meant he had "lost the ability to make certain decisions".
"In a sense, I'm being forced to make certain decisions and pick certain teams.
"(But) I'm not going to sit here and make excuses, that's what we have.
"We weren't far away tonight and I think us at our very best, even with the players we have out, is good enough."
Howe's side, who thumped Paris Saint-German 4-1 at home earlier in the pool stages, now face a difficult path to qualify for the knockout stages.
The manager told reporters "the game just came too quickly for us" after Saturday's 1-0 win over fellow Champions League participants Arsenal.
"After what the players have given in recent weeks, the game came too early."
Howe said it was "difficult to tell" if the team could still qualify for the knockout stages, but would "do our best to win our last few games."
"If the best version of ourselves turned up today, the result would have been different.
"Today's task was huge for us and ultimately we weren't good enough.