Winners and losers in Antonio Conte's new 3-4-3 Chelsea formation
In the second half of Chelsea's 3-0 humiliation against Arsenal, Antonio Conte finally moved away from the four-man defence that has underpinned the Blues' most memorable victories and most jarring defeats over the past four years.
He shifted to a 3-4-3 formation and instructed his wide midfielders to operate as wing-backs whenever the Gunners surged forward.
The experiment was repeated from the start against Hull City at the KCOM Stadium on Saturday. The result was a 2-0 win and arguably the most balanced performance Chelsea have produced under Conte, who hinted after the match that he may stick with his new formula.
ESPN FC takes a look at the men who stand to benefit most from the Blues' radical new look, as well as those with most to worry about.
1. Marcos Alonso
The Spaniard made several mistakes with his positioning during Chelsea's EFL Cup comeback win over Leicester City, and it's clear that Conte doesn't see his deadline-day signing as a reliable Premier League left-back yet.
But the role of left wing-back looks tailor-made for Alonso, who often operated on the left of midfield at Fiorentina and is a highly accomplished crosser.
With a defender covering behind, his errors should not be so consequential. His natural inclination to attack down the line will create dangerous overlap opportunities with Eden Hazard. More importantly for him, no one else in the Chelsea squad looks even remotely as qualified for the job.
2. Victor Moses
Handed his first Premier League start for Chelsea since May 2013 against Hull, Moses took his chance emphatically.
"Moses played an incredible game -- in defensive situations and offensive situations, he was fantastic because he was working very hard," Conte said after the match. "He deserved to play, and he showed me my choice was right."
It's easy to see why Conte values Moses so highly. He combines the strength and skill to keep the ball under pressure with an uncanny knack of committing defenders whenever he dribbles. Against Hull, he was a constant threat while diligently providing cover for Cesar Azpilicueta.
Conte also sees Pedro as an option for the right wing-back spot, but Moses is the man in position. Only a hamstring injury picked up at the KCOM Stadium can keep him out of the team if his head coach sticks with 3-4-3.
3. N'Golo Kante
Those hailing Kante as "the new Makelele" on his arrival at Chelsea failed to appreciate the precise nature of his role in Leicester City's remarkable run to the Premier League title.
In Claudio Ranieri's midfield the Frenchman was one of two roaming destroyers, rampaging across the middle third of the pitch with Danny Drinkwater to win the ball back and turn defence into attack.
This is why he has occasionally looked ill-disciplined and uncomfortable at the base of Chelsea's midfield trio -- never more so than when Mesut Ozil effortlessly swivelled away from him for Arsenal's third goal.
Kante has all the skills to succeed in Makelele's position in the long term, but right now a tenacious partnership with Nemanja Matic in Conte's 3-4-3 looks the best way to maximise all the gifts that made him so spectacular at Leicester.
4. Eden Hazard
After a dazzling start to the season, Hazard was at his anonymous worst against Liverpool and Arsenal. Both teams smothered him, blocking Chelsea's passes towards their star winger and doubling up on him whenever he did get the ball.
The weakness of Chelsea's four-man defence is that with Cesar Azpilicueta at left-back, Hazard has no one close or dangerous enough to lure away the second or third defender sent to nullify him.
Alonso on the left of a 3-4-3, however, means opponents can't so easily prevent the Belgian from darting inside onto his right foot if the alternative is allowing a gifted crosser unchecked down the line.
Hazard also enjoyed greater license to drift across the final third against Hull, moving centrally to find new passing angles with Costa and Willian and Hazard even popped up on the right flank at times.
The more freedom -- and less defensive responsibility -- Hazard is given, the more he will be able to influence matches.
5. Diego Costa
The form of the Premier League's favourite villain has rarely dipped below exceptional this season, regardless of how his Chelsea teammates are doing.
But too often Costa has shone in spite of the system. Against Liverpool and Arsenal he was a man on an island, completely isolated with Chelsea's midfield pinned deep inside its own half.
In Conte's 3-4-3 against Hull, Hazard and Willian were both encouraged to get much closer to Costa while Alonso and Moses provided attacking width, and it was no coincidence that Chelsea's opening goal arose directly from good combination play with Willian.
Costa has done incredibly well to score six goals in his first six Premier League matches this season but, with Chelsea's creators in closer proximity, he could quickly become even more dangerous.
1. Branislav Ivanovic
Conte's decision to field Azpilicueta as one of three centre-backs ahead of him against Hull was the culmination of a nightmarish 18 months for Ivanovic.
His form -- and standing among many Chelsea supporters -- is yet to recover from last season's disastrous Premier League title defence and, at 32, the growing sense is that the decline may be irreversible.
Ivanovic is out of contract next summer and desperately needs to play if he wants to earn an extension. There is no reason why the best version of his game couldn't earn him a place in Conte's three-man defence, but it's a version that no one has seen at Stamford Bridge for a worryingly long time.
2. Cesc Fabregas
The clamour among Chelsea supporters for Conte to restore Fabregas to his starting XI has quietened in the wake of last month's mauling at the Emirates Stadium, in which Arsenal ruthlessly exploited the regular chasms of space that opened up between the Spaniard and Kante and Nemanja Matic.
Conte simply didn't trust Fabregas not to compromise Chelsea's defensive system in a 4-3-3 formation, even with two designated destroyers around him. In a 3-4-3 the demand on the two central midfielders to be all-round contributors is even greater.
If Fabregas found it hard to convince his head coach of his usefulness in a three-man midfield, it's difficult to see his situation improving now.
If Fabregas' flaw is indiscipline, Oscar's weakness is inconsistency. The Brazilian who looked revitalised by Conte in Chelsea's first three Premier League matches was a helpless bystander as the Blues lost control against Swansea City and found themselves suffocated by Liverpool's pressing.
Conte responded by dropping Oscar against Arsenal, favouring Fabregas despite the Brazilian's inferior defensive attributes. Now neither man looks ideally suited to a role in the midfield hub of a 3-4-3, even if the Matic-Kante axis seen at the KCOM Stadium is nowhere near as easy on the eye.
4. John Terry
When he accepted a "different role" and signed a new one-year contract back in May, few expected Terry to play every Premier League minute this season until he left the Liberty Stadium on crutches last month.
In truth Conte could do little else. Prior to deadline day he lacked viable alternatives to his 35-year-old captain, and since the Swansea City match he has often desperately lacked Terry's composure and leadership.
All of this might lead many to the conclusion that Terry will remain as integral to Chelsea as ever when he returns from strained ankle ligaments after the international break, but Conte's shift to a back three changes the dynamic.
The Italian wants to play a high defensive line at Chelsea -- a concept fundamentally incompatible with a player of Terry's increasingly limited athleticism. In a 3-4-3 it is even more important to have mobile centre-backs who can survive without speedier protection from the flanks.
Azpilicueta, David Luiz and Kurt Zouma (when he returns) all clearly fit that bill, while even Gary Cahill and Ivanovic are better equipped for the task than Terry.
5. Michy Batshuayi
You could be forgiven for thinking that a formation that accommodates more attackers would be good news for Chelsea's back-up striker.
But 4-2-4 -- a system Conte has trialled in the EFL Cup this season -- would be a tactical change far more suited to Batshuayi than 3-4-3, which requires four men accustomed to operating on the flanks to supply one central striker.
That striker will clearly remain Costa, who is playing as well as at any time in his Chelsea career. Batshuayi's best moments this season have come alongside the Spain international in a partnership through the middle; putting the Belgian on either side would be an awkward use of his talents.
Batshuayi is full of promise and will make an impact for Chelsea this season. But if 3-4-3 really is Conte's plan, his path to the starting XI is no clearer.
Liam is ESPN FC's Chelsea correspondent. Follow him on Twitter: @Liam_Twomey.
Liam is ESPN FC's Chelsea correspondent. Follow him on Twitter: @Liam_Twomey.