Back room staff at Shakhtyor Karaganda killed a black ram, local news reports said, in what is understood to be a club tradition.
The animal was photographed yesterday - still alive - being wheeled in to the national stadium in the Kazakh capital Astana where the two sides will meet.
Shakhtyor's Russian-born manager Viktor Kamykov said: "We observed tradition. The lads took the initiative so that we sacrificed a ram ahead of this new stage for us, the Champions League play-off."
News website Vesti.kz said that a mullah from a local mosque had carried out the ceremony.
Shakhtyor players then went on to play a scratch game on the national stadium's artificial turf.
Shakhtyor fans immediately took to social media to say they could not lose.
"It would be a sin to lose now," said one.
Two thirds of Kazakhs are muslim although Karaganda - still a byword for remoteness in the former Soviet Union - has a very large German and Russian population.
Mr Kamykov, meanwhile, insisted his side would not be "whipping boys" despite describing his players as "newbies".
l BIG MATCH BUILD-UP - SPORT 42,43