Elfsborg left Celtic Park last night following their 1-0 defeat to the Hoops believing that they can turn their Champions League third qualifier around in Sweden next week.
It was a tough evening for Neil Lennon's side against the well-organised visitors but Kris Commons' second-half header gave the Scottish champions a narrow advantage to take to Boras for the second leg.
Elfsborg's English forward, James Keene, insisted that the Swedish champions have a "great chance" of overturning the deficit.
The former Portsmouth player said: "We are going into the game at home with confidence.
"Celtic Park was always going to be a tough place but I think we showed that we are going to ask a lot of questions at home.
"We are pretty happy with 1-0. We played pretty well. It is going to be a different game when they come to our place.
"I think we have a great chance, it is definitely not over."
Elfsborg boss Jorgen Lennartsson also believes his side are still in the tie.
He said: "They were the better side and deserved to win the game. "But I don't think Celtic should feel that the tie is over because it is not.
"It was a very good first half and we played exactly the way we wanted.
"In the second half we were too deep and did not have enough possession, didn't create any chances - maybe one - and they pressed us hard.
"We hoped we could defend to get a draw but we conceded one goal.
"It was not good but we think the game is still alive. "We have lost one of the last 25 games at home on our Astroturf.
"So it will be a different game, we have to attack and we will have the crowd on our side."
Commons, though, was bullish in his belief that Celtic will make it through to the play-offs.
He said: "It could be a vital goal in the grand scheme of things but I do think we can score in Sweden.
"Fraser (Forster) could have stayed in the changing-rooms. I don't think the ball touched his gloves.
"They were happy at 1-0. I think they would have been delighted at 0-0.
"But we are more than confident about going on the road and getting goals."