Lionel Messi found the net 15 minutes from time to nab what could prove to be a vital away goal, leaving the Blues with work to do if they are to remain on course for a second success in the competition.
The Premier League side famously overcome Barcelona in Catalonia six years ago en route to that maiden triumph, though, and they have more than held their own in other past tussles between the heavyweight clubs.
From 13 previous competitive encounters, in fact, Chelsea have won four and lost three, with the other six ending all square.
Another tight match is expected this week and, with that in mind, Sports Mole considers which of those expected to feature at Camp Nou would make it into a combined XI.
For all the strengths of Marc-Andre ter Stegen and back-up stopper Jasper Cillessen, there are not many better goalkeepers on the continent at this moment in time than Chelsea's Thibaut Courtois. The Belgian has kept 144 clean sheets in 344 appearances for the Blues, though he has conceded in each of his last four heading into this second-leg tie.
One man who simply has to feature in this side, meanwhile, is the ever-reliable Cesar Azpilicueta, who is more accustomed to playing in a back three these days but can also do a job at right-back. That is exactly where he features in this hybrid side, on the opposite flank to the attack-minded Jordi Alba - now into his sixth campaign with Barca but looking as dangerous as ever down the left with seven assist and two goals in La Liga this term.
With a 4-3-3 formation being used, the likes of Victor Moses and Marcos Alonso both miss out, as does Sergi Roberto due to the inclusion of Azpilicueta. The centre of defence is comprised of two Barcelona players, though, as Gerard Pique and Samuel Umtiti have barely given an inch away for a side boasting 17 clean sheets in the Spanish top flight.
Further forward there is a big decision to be made in the holding role as, despite Sergio Busquets's obvious talents - combining defensive work with an eye for a key pass - this side requires a rock in front of the back four and that is where N'Golo Kante is very much in a league of his own. The Premier League's 2016-17 Player of the Year is the best around at what he does, allowing other more attacking players either side of him to shuttle forward. With that in mind, Cesc Fabregas - a product of Barca's famed La Masia youth system - and Andres Iniesta are included to provide some midfield spark.
There is arguably less debate to be had in the frontline, however, as Lionel Messi and Luis Suarez continue to find the net on a regular basis for Barca, while Eden Hazard has been in inspired form for the Blues, even if they have endured a rather inconsistent campaign on the whole. Suarez and Messi, who tend to work in tandem these days in a 4-4-2 of sorts, boast 31 and 24 goals respectively, while Hazard has played a direct part in 21, seeing him get the nod over Willian and Pedro.