Issues Mourinho Must Address in Chelsea Defence to Maintain Premier League Dream
But just as they were dominant going forward against the Black Cats, defensive lapses saw the game go right to the wire when the Blues should have had things wrapped up well in advance of the referee's final whistle.
The game ended 4-3, and an excellent performance from Eden Hazard that ensured goals from Jozy Altidore, John O'Shea and Phil Bardsley proved little more than a consolation for Sunderland.
Poor defensive performances are beginning to creep their way into Chelsea's matches of late, with the events on Wednesday being far from isolated.
Just a few days previous, Chelsea had fallen behind after 14 seconds against Southampton due to an error in judgement, while a lapse in concentration saw them fall to a 1-0 defeat at the hands of Basel in the Champions League.
Indeed, they have conceded the first goal in their previous three matches, not to mention keeping just two clean sheets in 10 Premier League outings since late September.
Jose Mourinho will be concerned with this series of events, and if the Blues do not tackle their existing defensive deficiencies, it will impact how successful they are this term.
Bleacher Report looks at some key areas that must be addressed.
For a manager who prides himself on having his teams well drilled and organized, the three goals Chelsea conceded against Sunderland will frustrate Jose Mourinho more than most.
Sunderland kept themselves in a game that should have long passed them by, with all their goals on the night coming from set pieces.
Jozy Altidore fired the Black Cats in front when Chelsea failed to clear a free-kick, while John O'Shea and Phil Bardsley each scored from corners.
For football hipsters, set pieces may be frowned upon, but they provide managers with the only aspect of a game they can truly control.
Regardless of tactics and great team talks, the moment a team steps onto the pitch, the influence of the manager, in his dugout, reduces considerably. By drilling his players from set pieces, however, he ensures there's one area of the pitch he can control.
Based on Wednesday night's evidence, Mourinho needs to be doing much more work on the training pitch with this Chelsea team.
None of Sunderland's three goals were scored from open play, hinting that the Blues were indeed a soft touch when it came to set pieces.
Sunderland had evidently spotted a weakness ahead of the game and they came close to benefiting from it.
Against better teams, who will not be as charitable defensively as Sunderland themselves were, Chelsea's inability to deal with set pieces will come back to haunt them as the season progresses, and it must be addressed.
Against the biggest teams and in their most important games this season, Chelsea haven't been found out defensively on too many occasions.
It's when they have faced the so-called lesser teams in matches they are expected to win that the Blues have come undone. And their failure to remain focused on the task at hand has played a considerable role.
It was the case against Sunderland on Wednesday, when the Chelsea defenders seemed to switch off from their duties for Jozy Altidore's opening goal.
Andrea Dossena's free-kick had been deflected off the wall, but before any Blues players reacted, Jack Colback had passed the deflection to Altidore, who fired home from 12 yards.
John Terry was turned by his man and caught flatfooted while Altidore reacted quickly to everything that was happening around him.
It was a similar story just a week earlier against Basel in the Champions League.
On what was a night to forget for an all-round poor performance from Chelsea, they seemed to have done enough to scrape a draw in Switzerland until Mohamed Salah made the most of a defensive lapse, latching onto a long ball before eventually firing beyond Petr Cech.
For a team with Premier League and Champions League aspirations, being caught out by a simple crossfield pass is not only unacceptable—it borders on the disastrous.
It should have been cut out, but Branislav Ivanovic was caught napping for a moment and Chelsea eventually paid the ultimate price by losing the game 1-0.
As it transpired, results elsewhere actually meant that, despite defeat, the Blues progressed to the next round of the competition. In the latter stages, however, they will not be so fortunate, and in the Premier League, three points dropped right now could prove fateful.
History repeats itself—first as tragedy, second as farce.
When Michael Essien made his ill-judged back pass that led to Southampton opening the score at Stamford Bridge within 14 seconds last weekend, it was very much the latter.
We've seen it before with this Chelsea team—this season and at the same end, in fact.
David Luiz made a similar error against Cardiff City in October, underhitting a pass back to Petr Cech which Jordon Mutch capitalized upon, dinking his effort over the advancing goalkeeper to put Cardiff in front.
On both occasions, Chelsea have recovered to win the game (4-1 against Cardiff, 3-1 against Southampton). Yet, they cannot gift the opposition goals and expect not to pay the price at some point.
It carries a tone of complacency—that Chelsea's defenders are too composed and unaware of the dangers around them.
Jose Mourinho needs to drill focus into his players regardless of the opposition, and juvenile errors such as these need to be eradicated.
There have already been a few combinations used in defensive midfield for Chelsea this season: Lampard-Ramires, Mikel-Lampard, Ramires-Essien, Mikel-Essien.
At times they have impressed; others they've looked poor. It's why Jose Mourinho has rotated, looking for the best setup, but until he finds a defensive midfielder capable of impacting games in the way Europe's leading men often do, the Blues will continue to struggle.
Where will he find him? In the Blues' academy? By repositioning a current first-team player? Or in the January transfer window?
We don't know just yet, although what we are well aware of is how it will continue to impact Chelsea's performances—going forward and defensively.
In the modern game, it is vital a defensive midfielder screen the back line and help reduce the threat on goal by making interceptions, breaking up play or denying a playmaker space.
Right now, Chelsea do not have a player or midfield partnership capable of doing it consistently, and it shows.