Last year’s finalists conceded two goals in the first 21 minutes to exit 4-0 on aggregate, after losing their Round of 16 first leg 1-0 in London last month.
Tottenham Hotspur failed to show maturity and never put up a fight as they lost 3-0 to RB Leipzig in the Champions League on Wednesday, midfielder Dele Alli said.
Last year's finalists conceded two goals in the first 21 minutes to exit 4-0 on aggregate, after losing their Round of 16 first leg 1-0 in London last month.
"After the first one (goal) went in it didn't change much but we conceded too many chances as a team," Ali told BT Sport. "It's hard to come back from those two goals. We had to show our maturity and fight and we didn't do that."
Marcel Sabitzer scored in the 10th and 21st minutes and Tottenham had only one shot on target in the first half.
They earned their first corner in the 43rd minute and Jose Mourinho's team, missing several key international players through injury, lacked any fighting spirit.
"We can't use excuses, we still have quality on the pitch. We are missing good players but that happens," Ali said. Spurs were without top strikers Harry Kane and Son Heung-min as well as fullback Ben Davies and midfielder Steven Bergwijn.
"The players coming in have to step up and we haven't done that today. We apologise to the fans. To go out and lose like that, they deserve better," Ali added.
Spurs have now gone six games without a win, the longest such run in coach Jose Mourinho's entire managerial career, while his Leipzig counterpart Julian Nagelsmann became the youngest at age 32 to reach the competition's last eight.
"We have to fight. We can't be in the position we are in in the league, we can't hide," Ali said. "This hasn't been a good season for us. The reality is we are in a bad situation, confidence has gone at the minute."
Tottenham are eighth in the Premier League, seven points behind Chelsea in the fourth Champions League qualifying spot.