Borussia Dortmund striker Serhou Guirassy said his side had sealed their fate with a poor first leg performance in Barcelona last week, despite a much improved display in a 3-1 home win on Tuesday.
Trailing 4-0 from the first leg, Guirassy gave Dortmund a glimmer of hope with an early penalty and then a second goal just after halftime.
But an own goal effectively killed off the tie in Barcelona's favour despite Guirassy completing his hat-trick with 14 minutes left.
"They're a great team, we're also a great team, we showed that today. It's a shame the gap was too big in the first leg," Guirassy told Amazon Prime.
Guirassy moved up to 13 goals in the Champions League this season, more than any other player in the competition and a club record.
"It's great to be the top scorer in the Champions League; there are some great players. Being first also means that I'm a great scorer, but without the team, I can't do it alone."
Dortmund defender Niklas Suele, who won the Champions League with Bayern Munich in 2020, agreed "that we messed it up in the first leg... the performance was too bad in Barcelona."
The German side looked to have made it 4-1 on the night through Julian Brandt with 11 minutes remaining, but the goal was disallowed for offside and Barcelona progressed 5-3 on aggregate.
"I think it would've been an exciting last 10 minutes," said Dortmund midfielder Pascal Gross.
"Until the last minute we played to show we believed so the stadium would believe in it.
"We're out because of the bitter game in Barcelona, but you can see we are good enough to go toe-to-toe with them."