The Danish side returned from their winter break to lose 1-0 on Friday to struggling Esbjerg.
Despite injuries to players such as Viktor Fischer, Jonas Wind, Nicolai Boilesen and Robert Mudrazija, they have decided to sell Cyprus international Pieros Sotiriou to Astana before Thursday's first-leg clash at the Parken Stadium.
Neil Lennon's side are in top form, having won nine out of nine in all competitions since returning from the winter break and since losing to Rangers at the end of the year. They lead their Old Firm rivals by 10 points at the top of the Ladbrokes Premiership having played a game more.
Solbakken, who was in his first spell as Copenhagen boss when they beat Celtic 3-1 in the 2006/07 Champions League group stage, after losing 1-0 in Glasgow, said: "It is a 50-50 tie here.
"If you see Celtic's last nine games and how they have coped with the loss against Rangers in the league, they have had a tremendous comeback.
"Their stability has been good. They have had very few changes in the line-up from game to game, they have played 3-5-2 with great success.
"They have three powerhouses at centre-backs, they have strength in midfield and the partnership up front has worked well for them.
"They have found a different rhythm from us, we have played friendlies and had a very weak second half of the opening game of the year.
"We have had a few struggles with short and long-term injuries and at this moment there are only four or five players who are definite starters in my line-up. Mr Lennon has more security in that way.
"But in one game here, anything can happen as we have shown so many times. If one good thing can happen for us tomorrow and we carry a good result and performance into the second game then obviously anything can happen.
"There is not that big a difference between the teams and I will be disappointed if we don't have our moments tomorrow, create something, be good on the ball and dominate for periods.
"But Celtic have been great in Europe, beating Lazio twice, beating Rennes from France so they are rock solid and that is credit to the manager of Celtic, coming after Brendan Rodgers and doing so well."
The video assistant referee (VAR) system will be in operation on Thursday night but the former Wolves boss is wary of the system, which has come in for so much criticism in England this season.
The 51-year-old Norwegian said: "Neither we nor Celtic are very experienced with VAR.
"There is no VAR in Scotland so we are on even terms there. From what I have seen so far with VAR, I like the idea but don't like the way it works.
"It takes too much power from the referee. In terms of the words clear and obvious, I think that has been messed with really badly in too many situations.
"There is so much that is not clear and obvious."