A 1-0 defeat to Anzhi Makhachkala in Moscow, the Reds' second in Group A, saw them slip from top spot in the table.
Young Boys, whom they beat 5-3 in Switzerland, visit Anfield in a fortnight but even a win may still not guarantee progress if the other result goes against them before the final trip to face Udinese next month.
"It's a very tight group," said Rodgers.
"It was always going to go down to the last game. The next one is now a big game for us now against Young Boys.
"We just move on to the next game in the group and that is one we have to focus on because we have to win."