Neil Lennon's side have learned their potential Champions League play-off opponent.
Slavia Prague lie in wait for Celtic in the Champions League play-off if Neil Lennon's side defeat CFR Cluj.
The draw was made on Monday nd the Scottish champions would face a tough test against the Czech title winners if they are to reach the elite stage.
First, they have to overcome Cluj in the third qualifying round.
Slavia won the Czech First League by four points last season, finishing ahead of Viktoria Plzen and city rivals Sparta.
Though they were knocked out of the Champions League qualifying by Dynamo Kyiv last season, they went on a run to the quarter-finals of the Europa League after knocking out Genk and Sevilla.
Celtic have to make their way through four stages to reach the group stage of the Champions League. They began their campaign with a 5-2 aggregate win over FK Sarajevo and then thumped Estonia's Nomme Kalju 7-0 over two legs.
The first leg of their third round tie against Romanian champions CFR Cluj will be played on Wednesday night with the return leg at Celtic Park next Tuesday.
If Celtic fail to progress from their Champions League tie then they will face Sherrif Tiraspol or AIK in the Europa League play-off round. The Scottish champions would be at home in the first leg.