Nobody saw Chelsea coming the last time they won the title. The key moment came in the sixth game of the season when they found themselves 3-0 down at half-time away at Arsenal. They’d lost at home to Liverpool the previous week and drawn at Swansea the week before that. Their manager, Antonio Conte, having tried to accommodate himself to the squad decided enough was enough: the squad had to bend to him. At half-time he switched to his preferred back three and in the comforting drabness of a goalless second half of a game that was already lost, was born the revolution.

Chelsea won their next 13 league games and by the time anybody had worked out how to deal with their 3-4-2-1, with N’Golo Kanté and Nemanja Matić an apparently impenetrable shield at the back of midfield, it was too late. There was no European football to worry about – the previous season had seen José Mourinho’s meltdown and a 10th-placed finish – and so Victor Moses and Marcos Alonso remained fresh enough to keep tearing up and down the field at wing-back. Elsewhere the stars aligned: Manchester City were still getting used to Pep Guardiola in his first season in English football, Arsenal were still in their late-Wenger drift, Liverpool still building under Jürgen Klopp, and so Mauricio Pochettino’s Tottenham were Chelsea’s closest challengers. But 93 points would probably have won the league whoever came second.

Eight years later, could it be happening again? Again, Chelsea started in chaos, with Raheem Sterling releasing a statement protesting his omission seconds after the team sheet was released for the opening game of the season, a 2-0 home defeat to City. Again, they have a manager who has brought unexpected clarity. Again, underwhelming performances last season have lifted the burden of European football; although Chelsea have the Conference League to play in, Enzo Maresca has turned what could have been a chore into a benefit, creating what is effectively a shadow squad who, in a largely pressure-free environment, have become familiar with his style of play and can step up when required.

Does that mean Todd Boehly and Behdad Eghbali knew what they were doing all along? That perhaps would be going too far and it remains unclear how the splits in their leadership reported back in September have been resolved. After all, if you throw enough money at a project, things have a tendency to click eventually.

But with each passing week, Maresca appears a more inspired choice as manager. There remain potential PSR pitfalls ahead, while it says much for the wastage of the project that there are 24 senior players brought in under the current ownership at a cost of £550m who have started fewer than three games for Chelsea this season (three of those have, admittedly, already been sold – at a combined loss of £20m). Maresca’s greatest achievement so far, perhaps, has been to sift through the box and work out which pieces do not fit.

It does seem to be working. Sunday’s 4-3 win over Tottenham was Chelsea’s fourth in a row in the league, and came despite a couple of Marc Cucurella slips gifting Spurs a two-goal lead. With 35 goals Chelsea are comfortably the league’s top scorers. Although they have played one game more than Liverpool, they have closed to within four points at the top, close enough that, even with a game in hand, Liverpool will be able to sense their breath on their necks.

History says that teams this far ahead at this stage usually go on to win the title, but the sample size is limited. Being the lone frontrunner for a protracted period is tough, and superbly as Arne Slot has done so far, he has been fortunate with injuries and the way that fixtures have fallen. Nobody can be sure how Liverpool will react in adversity. City are in the grips of the worst crisis since Guardiola arrived at the club. Sunday’s draw with Fulham demonstrated that Arsenal, having been unfortunate with injuries and having played many of their hardest fixtures, are still struggling for fluency.

After 15 games, this is a season with, at its top end at least, a pleasingly old-fashioned feel. Everybody bar Liverpool has looked fallible, and there is a sense of uncertainty also about them. At the same time, the league’s large middle is full of sides – the likes of Nottingham Forest, Bournemouth, Brighton and Brentford – who on their day can upset anybody. Liverpool may yet run away with it, but for now there is a satisfying sense of unpredictability, and that means that for all that Maresca and his players may try to deny it, Chelsea – unexpectedly – are firmly in the title race.

Jonathan Wilson brings expert analysis on the biggest stories from European soccer

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On this day

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It would have been much easier for the UK if Australia had qualified for the 1966 World Cup, hosted in England. But, ill-prepared, they lost 9-2 on aggregate to the Democratic People’s Republic of Korea, which created a major headache for the Foreign Office. Although the Korean War, to which Britain had committed almost 100,000 troops and its Far East fleet, had ended with an armistice in 1953, the UK had never formally recognised the northern part of Korea as a sovereign nation, nor had any formal peace treaty ever been signed.

That created three major areas of concern: the anthem, the flag and the terminology to be used. “North Korea” it was decided was accurate without necessarily conferring statehood. Agreement was reached that the flags of all 16 competing sides could be flown at every game. But what to do about the anthem? On 9 December 1965, a clever diplomatic solution was found: anthems were to be played not before every game as is usual but ahead of only the opening match and the final, the (correct) assumption being that would mean the North Korean anthem would never be heard, although they did pull off a major shock by eliminating Italy in reaching the quarter-final.

• This is an extract from Soccer with Jonathan Wilson, a weekly look from the Guardian US at the game in Europe and beyond. Subscribe for free here. Have a question for Jonathan? Email soccerwithjw@theguardian.com, and he’ll answer the best in a future edition