Roma have not won since their 5-1 hammering of CSKA Moscow on matchday one, but still sit second behind runaway Group E leaders Bayern Munich.
Another victory over CSKA on Tuesday would leave the Serie A side on the brink of reaching the knockout stages, and three points would guarantee them second spot if Bayern beat Manchester City.
And head coach Garcia has urged his players to seize the moment.
"We have our destiny in our own hands tomorrow and an advantage - the result from the first game," he said.
"After the draw no one thought we'd go into the fifth game with a chance of going through.
"Having a chance to qualify with tomorrow's game means we have had our say and we need to continue to do so.
"Although we beat them in Rome, we still come here with a lot of humility, but we'll still play to win the match as we always do."
Garcia has defensive problems for the trip to Russia with no fit right-backs in his squad.
"We'll need a right back tomorrow," the Frenchman added. "Either [Michele] Somma, [Alessandro] Florenzi or someone else I've got up my sleeve [will play there].
"Maicon is not in a condition to play tomorrow. He's not trained with the team.
"I had considered bringing everyone who had a chance of playing, yesterday sadly we had to make do without Maicon and [Vasilis] Torosidis."
