But Guus Hiddink will find plenty of cause for optimism in a performance which gives his side every chance of reversing the deficit when Paris St Germain visit Stamford Bridge.
Here's a look at five things we learned from Chelsea's performance in the Parc des Princes:
1. New centre-back pairing stepped up
The prospect of missing both John Terry and Kurt Zouma from the back-line in Paris must have filled many Chelsea fans with dread.
Neither Gary Cahill nor Branislav Ivanovic have covered themselves in glory so far this season yet these were the men charged by Guus Hiddink with stopping the likes of Zlatan Ibrahimovic.
But the pair rose to the occasion, each producing a towering performance to hold back their in-form hosts and bolster Hiddink's options not just for the second leg, but the rest of the season.
2. Courtois is a worthy successor to Cech
Chelsea fans could not help but cast envious glances across London this season as their former hero Petr Cech continues to provide the backbone to Arsenal's title charge.
Courtois has taken a bit longer to earn the true affections of the Chelsea fans but in Paris he reminded them that perhaps Jose Mourinho was right in promoting him to first-choice keeper in west London.
True, Courtois might have done better with Cavani's winning goal, but he kept his side in it with superb stops to deny Ibrahimovic, Angel di Maria and Lucas Moura.
3. Hiddink has steadied the ship
Wednesday's defeat was the first for Chelsea since Hiddink replaced the ailing Mourinho in the wake of a loss at Leicester in January.
Rather than being seen as a negative, it puts the improvement made under the impressive and understated Dutchman into sharp perspective.
Chelsea might have left it too late to muscle back in on the top four - and even with their recent improvement, winning the Champions League is surely beyond them.
But it seems certain whoever replaces Hiddink for the start of next season will have a tough act to follow - and a much better set of options at his disposal.
4. Eden Hazard's hopes of PSG move look further away
If Eden Hazard wished to use Wednesday's game as a shop window for a lucrative future transfer to the French capital - which he said beforehand would be "difficult to say no to" - then he failed abjectly.
It seems years since Hazard was being feted as the PFA Player of the Year following a series of devastatingly effective performances for his club last season.
This season, his woeful form has neatly symbolised his club's crashing fall from grace. Sometimes disinterested and often outclassed, Hazard cut a desperate figure once again.
5. Ramires will be missed
The Brazilian's departure to China during the January transfer window came as a major surprise to many Chelsea watchers who reckon his powerful, incisive runs are just what this side are now lacking.
His absence was again evident in Paris, with his fellow Brazilian midfielder Willian once again left over-worked in the middle as he sought desperately for the kind of link once afforded by his countryman.
If anything can be used as a benchmark for the rising force of Chinese football, then it is surely the departure of such an influential player from a club which is quickly beginning to discover that money cannot buy everything.