Christian Eriksen admitted Tottenham were not good enough to deserve anything other than Europa League elimination after a 2-2 draw against Gent resulted in a 3-2 aggregate loss.
Eriksen opened the scoring for Tottenham in the first half, but it all went wrong before the break as Harry Kane scored an own goal and Dele Alli was shown a red card for a horrible lunge on Brecht Dejaegere six minutes before half time.
Victor Wanyama's superb second-half strike gave Tottenham temporary hope but Jeremy Perbet killed it late on as he capitalised on a defensive mix-up to score.
"We are very, very disappointed with what we achieved today, and in these two games against Gent," Eriksen said.
"In the first half they didn't have a shot on target but they still got a goal and this gave them confidence.
"Also the first game that we lost, it makes it much more difficult. We gave it away on a stupid mistake but they took their chance very well. We were not good enough."
Spurs could complain that the corner from which Kane put into his own net should have been a goal kick, but Eriksen said they had to blame themselves.
"Overall we did what we could and the ref was not on our side," he said.
"I haven't seen if it was a red card but we showed good character with 10 men. We had our chances, but when they scored to make it 2-2 it was a big punch.
"We can't blame the ref but he could have made it easier if it shouldn't have been a corner. We could blame the ref but we had our chances and at the end of the day we were not good enough."
Manager Mauricio Pochettino said he was proud of his players despite the loss.
"It was very disappointing," he said. "I think once again we were excited to play today in front of our fans and we started the game very well and scored a goal. The tie was open.
"But we conceded a goal with their one action of the first half, an own goal, and then it was more complicated with the sending off of Dele Alli.
"In the second half we played with 10. We were very brave, we created chances and scored the second goal to make it 2-1. Then we need one more to go to the next round, but we conceded at the end. Still, I feel proud because in the second half we showed great energy."
Spurs have conceded more goals in four European games at Wembley this season (6) than in 12 league games at White Hart Lane (5).
And Gent became the first Belgian side to eliminate English opposition in major European competition (excluding qualifiers) since Standard Liege knocked out Everton in the 2008-09 Uefa Cup.
Manchester United, who beat French side Saint-Etienne 4-0 on aggregate, will be the only British side in the last-16 draw today.
Tottenham, who remain without a trophy since 2008, will focus their attention on trying to catch runaway Premier League leaders Chelsea.
Third-placed Spurs host Stoke City at White Hart Lane on Sunday (1.30pm).