In September 2016, following two damaging defeats in a row to fellow title contenders, Antonio Conte initiated a radical tactical shift that revolutionised Chelsea's prospects. The change to a three-man central defence bore instant fruit with a 13-match winning run and the rest is history.
Fast forward 16 months and it might just be time for Conte to instigate another tactical overhaul. The outlook doesn't look nearly as bleak as it did after those losses to Liverpool and Arsenal last season, even if there is no chance of retaining the title, though there is no denying that Chelsea seem to be stuck in a holding pattern.
Since the start of 2018, Chelsea have failed to win a game in five attempts in all competitions, drawing all of their matches. They eventually prevailed against Norwich in the FA Cup but only after a 1-1 draw was decided on penalties.
The main issue has clearly been a diminished goal return. In those five games there have been three goalless encounters and just three goals scored by the Blues. Thankfully, Conte can call upon the joint-best defence in the Premier League but, if this situation continues, then Chelsea's chances of qualifying for next season's Champions League will go from probable to possible and to hopeful.
The issue largely stems from the system that Chelsea are playing. In an attempt to stiffen up the midfield, Conte has put an extra man in there, withdrawing one of the wide forwards.
While certainly more defensively pragmatic, this has had the knock-on effect of placing even greater pressure on Eden Hazard's shoulders to either unpick defences or find the back of the net himself. With the vast majority of attacks now funnelled through the Belgian international, opposition managers know that if they shut down Hazard, they are likely to shut down Chelsea.
The 3-5-2 still allows the team to have width but that is now solely supplied by the wing-backs with Hazard adopting a free role and Alvaro Morata the designated target man. Avenues of attack are more limited as a result and increasingly rely on some genius from Hazard to make the difference.
Against perceived lesser opponents Conte has reverted to the 3-4-3 system that swaggered to the title last season. It has the added advantage of providing multiple angles from which to get at opposition defences. The wide forwards can double up with the wing-backs to create overlaps. The shape is less rigid and allows for the swapping of positions across the front line. Runs are harder to track and space can even be created for centre backs to push forward.
But its limitations have also been exposed, hence the shift to 3-5-2. A two-man midfield is hard to pull off effectively on a regular basis, now that other sides have educated themselves in how to counter those playing three at the back.
It might be possible if Chelsea had the right personnel but, at present, they don't. N'Golo Kante is tailor-made for it but Cesc Fabregas lacks the dynamism and Tiemoue Bakayoko lacks the confidence.
Danny Drinkwater might make a good fit but his inconsistent displays are symptomatic of a player that arrived at the club injured and is still playing catch-up. Perhaps new signing Ross Barkley will fit the bill but it's a lot to ask of a player that has only just arrived at the club having not played a competitive game all season.
If Chelsea copied Man City's approach and played a pressing, possession-based game then those midfield glitches can be papered over. But such tactics take a while to successfully implement and do not happen overnight. Even City's current dominance was at least a season in the making.
It might sound obvious but in the short term, Chelsea simply need to start converting more of their chances. In all of their recent draws, they have created enough decent openings to have emerged with victory. The problem is that with each missed chance comes added pressure, especially on Morata who is enduring a particularly tough spell.
It would help if more goals were being supplied from other areas, though 3-5-2 places almost all the goalscoring responsibility on the "2." Thankfully, Marcos Alonso has consistently chipped in, though more can and should be expected from Fabregas, Bakayoko and -- when selected -- Willian and Pedro Rodriguez.
Last weekend's classic between Liverpool and Manchester City has cast Chelsea's current malaise in an even more unflattering light. Defending resolutely, however, is just as much of an art form even if it is not nearly so sexy and at least Chelsea are still extremely good at that part of the game.
Conte now needs to find a way to marry that resolve with something dynamic and unpredictable at the other end of the pitch that doesn't solely require Hazard to keep pulling rabbits out of the hat. It doesn't have to be as radical as events in September 2016, but some type of tweak is needed.