Boss Neil Lennon refused to write off Celtic's chances of booking their place in the Champions League despite their 2-0 defeat to Shakhter Karagandy.
Goals from Andrei Finonchenko and Sergei Khizhnichenko handed the Kazakhstan champions a first leg advantage.
But Lennon has faith in his players to salvage the play-off tie in next week's second leg in Glasgow.
He told BBC Radio Scotland: "It's a disappointing result.
"We should have scored and that would have put a different complexion on the tie.
"It's not over yet. We've got to go back to Celtic Park.
"There is plenty for me to chew on in terms of chances but Shakhter didn't surprise us with the way they played.
"We knew they would throw balls forward and we should have dealt with the first one a lot better.
"I don't know how many chances we had tonight - clear-cut ones as well - but if you don't take your chances you make life difficult for yourself.
"I'm not down and out just yet."
Lennon admits improvement in terms of some of the individual displays will be necessary at Celtic Park.
He said: "There are a few players who will be disappointed with their performances tonight.
"They've got to get better very quickly."
Steven Mouyokolo and Virgil van Dijk were both handed their European debuts for the Hoops, as they started in central defence together for the first time, with Efe Ambrose named on the bench.
Lennon added: "Efe has been in South Africa, Aberdeen and now another flight to Kazakhstan.
"I wanted the extra height to cope with the aerial bombardment that we were going to get.
"In the main, we dealt with it okay. We just switched off at one throw-in.
"I didn't really feel uncomfortable in the game at all. I thought we would score.
"But the fact that we didn't just makes it that little bit more difficult now."
Asked if the loss of key players, such as Victor Wanyama, Gary Hooper and Kelvin Wilson, contributed to the result, Lennon said: "Possibly.
"I still think we've got enough in the squad to come through the tie so that's what we will endeavour to do."