Chelsea launched the post Andre Villas-Boas era in winning fashion as second half goals from Juan Mata and Raul Meireles secured a 2-0 victory over Birmingham in an FA Cup fifth-round replay at St. Andrew's.
After a goalless first half, caretaker boss Roberto Di Matteo saw Mata break the deadlock eight minutes after the restart.
Then a superb 59th minute strike from Raul Meireles doubled Chelsea's lead to secure a home quarter-final tie with Leicester.
They could even afford to see a Mata penalty saved by Birmingham keeper Colin Doyle.
Chelsea caretaker-manager Roberto Di Matteo - in charge until the end of the season - spared a moment for his old boss.
He told ITV1: "My thoughts tonight go to Andre."
Di Matteo added: "I think the attitude was right, the commitment, the passion was there.
"It was important tonight to go through to the next round, for our club and for our supporters.
"We have two months left to the end of the season. We have to try to achieve what we have set ourselves for this season.
"It's only possible if the 25 players in the squad are a little bit unselfish and work together."