But the Celtic boss concedes that is simply a reflection of where Celtic are, and that the Europa League - into which the now drop - is their level at this point.
That would not cut any ice with the 200 Celtic fans who vented their spleen outside Celtic Park following the 1-0 defeat to Maribor which saw the Slovenians progress to the group stage draw on a 2-1 aggregate.
But Deila is in no mood to gloss over the decline he has been charged to turn around. In echoes of his comments after they had lost 6-1 on aggregate to Legia Warsaw, only to be re-instated through a UEFA ruling, Deila said: "In the end, it was only what we deserved because we were not good enough.
"We haven't deserved to go to the Champions League.
"That's the level now, and what we have to work up from.
"There are no excuses. I believe we had a good enough team to go through, but we didn't do it.
"I know we're going to get a good team, but we need to get some signings."
That is will not pacify the fans who protested after the defeat, and the manager said: "I really understand that.
"But, we have to be honest, we haven't been good enough."