Of course, they didn’t make it easy for themselves. It wouldn’t be Chelsea if they did. This, perhaps, has been the underlying theme of Frank Lampard’s first half-season: they are a team of wildly undulating fortunes who are often weakest when they appear at their strongest, and strongest when they appear at their weakest.

But once the nervous final minutes had been negotiated, once they could puff out their cheeks and dry their brows, Chelsea could savour a job circuitously well done.

For all their ordeals and imperfections, this is a team who sit fourth in the Premier League table and now have a Champions League last-16 tie awaiting them in the new year. Moreover, they thoroughly dominated for large periods here, at least until the screwball climax that followed Loic Rémy’s late goal. Yes, they still struggle to finish teams off. Yes, they still look painfully vulnerable in defence. But when they’re good, it can be extremely fun to watch.

“Personality” was the buzzword that Lampard invoked in advance of the game. This could be read in one of several ways. Maybe Lampard was challenging his side’s mettle.

Maybe, with the January window looming, he was trying to prick a few egos. Or perhaps he was simply appealing to their expressive side: an entreaty to keep inventing, even with the stakes at their highest. In which case he will have been quietly impressed with one player in particular.

Christian Pulisic did not score or assist a goal. He made just 19 passes and saw far less of the ball than the busy Willian on the opposite flank.

And in many ways this has always been the major criticism of him: that for a player of such natural gifts he is rarely as straightforwardly impactful as he should be. But here he demonstrated what he does best: running a game without – for the most part – appearing to do much of interest at all.

Partly, of course, this is simply the nature of the creative midfielder. The creator needs to play on the off-beats, to feel the game on a different wavelength from everyone else. In the modern game this is a doubly difficult task, because as well as attacking to a syncopated rhythm, the creator is also usually required to defend to a conventional one.

Like Eden Hazard, the man he was putatively signed to replace, Pulisic likes to start outside the defender’s eyeline, whether cutting in from the right flank as he did at Borussia Dortmund or on the left as he does at Chelsea.

He absorbs the ball with a deft first touch and a tight turning circle. But there are differences between them, too. In his barrelling energy and provocative runs, Hazard wants to be seen at all times. Pulisic, by contrast, wants to disappear.

This, in many ways, is the very essence of Pulisic: a high-speed game of hide and seek, in which the object is to elude detection until the last possible moment. He wafts and he hovers. He sprints and he skims. A simple Pulisic run will often see him change speed two or three times. Even when he picks up the ball, he is still trying to disappear: weaving through wormholes, drifting rather than waltzing past players with a snowy paddle of the feet.

Perhaps his most telling contribution here was the spectral run he made for Tammy Abraham’s goal, appearing in the left channel to gather N’Golo Kanté’s flick, spiriting the ball to the edge of the penalty area, laying it off to Willian with a simple economy of movement.

But there were many other such moments over the course of the game: eight dribbles in total, along with plenty of the usual tidy tracking without the ball. And as the boisterous Lille fans serenaded their former idol Hazard, Chelsea fans serenaded their current one: a player who, for all the deadly expectations invested in him, looks to be making good on his promise.

Pulisic’s entire career has, in a sense, been a case of managing these expectations. The teenage prodigy, the finest male player America has ever produced, the new Hazard: none of these labels was ever going to work to his benefit. And in retrospect it’s easy to see why it took him so long to settle at Chelsea. It was always going to take a while for his team-mates to attune themselves to his inimitable cadences, for fans to work out what, exactly, he was doing out there.

Sterner challenges lie ahead: a relentless winter schedule, a European heavyweight in the round of 16. But for now Pulisic feels like a perfect analogue for Chelsea as a whole: a player with the capacity to surprise out of nowhere, to lurch from shadow to spotlight and back again, the ghost in a clanking, alluring machine.