With Chelsea only three points behind leaders Manchester United in the Premier League, they must harbour genuine hopes of winning both trophies now.
After losing the first leg 2-1 there were nerves aplenty at Stamford Bridge, but they were settled somewhat with only four minutes on the clock as the hosts' barnstorming start led to a crucial opener.
Essien was fouled down the right and when Joe Cole swung in the cross, Ballack was on hand to plant a header downwards and across the keeper into the far corner of the net.
Chelsea had started like a train and Salomon Kalou scampered down the left and pulled the ball back for Cole to impudently flick it against the right-hand post with Volkan well beaten.
But having made such a fine start, Chelsea inexplicably dropped the tempo and began to allow Fenerbahce a route back into the contest.
The mood of the visitors improved when Blues keeper Cudicini limped off clutching his hamstring, replaced by Portuguese substitute Hilario.
An injury to Cudicini was the only blemish on Chelsea's night
With Petr Cech out for at least another two weeks with his facial injury, a problem for Cudicini must have been the last thing boss Avram Grant wanted at such a key stage of the season.
Soon after, Hilario was rooted to his line as Lugano sneaked in at the back post to meet an Alex free-kick, but he wastefully headed off target.
Chelsea's increasing willingness to gift possession away continued to make the contest closer than it might have been and only served to give the visitors hope.
Didier Drogba tried to increase the Blues' lead, but twice the big striker saw shots from distance fall into the arms of Volkan.
Fenerbahce brought on former Chelsea striker Mateja Kezman on the hour mark in place of defensive midfielder Claudio Maldonado as they went searching for a goal that would turn the tie around.
Chelsea nearly wrapped it up when Drogba forced Volkan to parry away his 25-yard free-kick, before the Turks went close twice in agonising fashion.
First, substitute Ugur saw his deflected volley scrambled off the line by Hilario, before first leg hero Colin Kazim-Richards stung the palms of Hilario with a 25-yard drive.
After Essien picked up a needless booking for throwing the ball away which will keep him out of the first leg against Liverpool, he got to the byeline and crossed for Lampard to tap in.
It was no more and no less than they deserved for a display which failed to sparkle but got the job done.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.