After back-to-back Last 16 exits, Manuel Pellegrini's side look on course to make it third time lucky and reach the quarters as they hold a 3-1 lead over Ukrainian champions Dynamo Kyiv ahead of Tuesday's second leg at the Etihad Stadium.
"It is the first time we have a chance to go forward to the quarterfinal. It's a big step for the club, for everyone," Fernandinho told City TV.
Saturday's goalless draw in the Premier League at third-from-bottom Norwich City has left the Manchester club nine points behind leaders Leicester City and just two points above fifth-placed West Ham United with nine games remaining.
Fernandinho was wary of missing out on Champions League football next season, but also refused to write off his side's title chances.
"We have nine games to play and, even if we don't have the chance to be champions, we have to finish in the top four," he said.
"There is always a chance (of the title), especially with this team. No one gives up, fight to the end."