Real Madrid coach Zinedine Zidane admits he was "a bit angry" his side conceded a 2-0 second-half lead to draw with Borussia Dortmund.
Two goals from Karim Benzema, the second his 50th in his 88th Champions League appearance, appeared to put the home side in control.
But Pierre Emerick-Aubameyang's 19th goal in as many games this season was followed by an 88th-minute equaliser from substitute Marco Reus which meant Dortmund finished top of Group F.
"When you see how the second half went, you get a bit angry," Zidane said. "We had the game in our hands but this is football. You need to carry on right to the end.
"There were a lot of chances to score the third goal. Instead, we got Dortmund back into the game. Dortmund deserved first place. They demonstrated how strong they are.
"They're a strong side who make life difficult and at the end of the day we needed to be a bit more on it, but it's in the past now. I'm very proud of the players, their hard work, the things they did. The group is probably fair with us second and them first."
While Zidane confessed to mixed emotions, Dortmund coach Thomas Tuchel enjoyed the experience.
"Matches with Dortmund are something special but unnerving," he said. "We did pretty well at the beginning. After that there were a lot of mistakes and wrong decisions.
"For the decisive goal it looked like Aubameyang had crossed it one touch too late but luckily he did not and Reus was able to arrive at full speed and bury it. Finally it was a happy outcome for us."