Spurs were held to a 2-2 draw by Gent at Wembley which resulted in them losing 2-3 on aggregate on what was an extremely disappointing night for the North London club.
Tottenham were reduced to 10 men late in the first half when Dele Alli was shown a straight red card, which came after the referee wrongly awarded Gent a corner despite the ball coming off a Gent player.
From that corner, Harry Kane scored an own-goal to level it at 1-1 but Danish playmaker Eriksen, who scored the opener, says the referee cannot be blamed as Spurs missed a number of chances over the two legs.
"Very hard, we are very disappointed on what we achieved today and what we achieved in these two games against Gent, so very disappointed," he told BT Sport.
"Of course they have not a shot on target (in the first half) and still get a goal, and they had confidence from the first game.
"That made it more difficult for us.
"We weren't good enough in our finishing and final passing."
Eriksen added: "Overall we did what we could, the referee wasn't on our side either. I haven't seen if it's a red but we took a big hit.
"We had enough chances.
"We can't blame the ref and of course it would have made it easier, but we should do better in that situation. We can blame the ref but it was our own fault, we had our chances over there, but we just weren't good enough."
Asked what were the positives of tonight's match, Eriksen said: "Not much, not much."