For a figure as volatile as Diego Costa, there was something distinctly predictable about all of this. The Chelsea striker had been offered an immediate return to the starting lineup after an unsettling period disrupted by lower back spasms and Chinese whispers, and ultimately that absence at Leicester last weekend. Yet here he was departing four minutes from time with the majority in this arena chorusing his name, to be greeted by a thumped hand clap from Antonio Conte on the touchline, as the man who had paved the way for an eight-point lead at the top. His scriptwriters should take a bow.

Chelsea have no interest in selling their leading scorer this month, whether Tianjin Quanjian or any of their Chinese Super League rivals are tempted to offer £80m, £100m or indeed £150m for his services. His long-term future will have to be properly addressed with the player and his agent, Jorge Mendes, in the summer, of course, but for now reintegration already feels almost complete unless those back pains return with a vengeance. The forward was at his committed best here, working feverishly whether leading the line or dropping deep to assist his team-mates. He played the role of “Costa the manager’s dream”, as he has done almost all season, to perfection.

Hull will take heart from their rugged resistance as they contemplate their ongoing battle against relegation, and could justifiably bemoan the non-award of a penalty for Marcos Alonso’s foul on Abel Hernández when their deficit was only one, but this was always going to be the Spain forward’s day. “People were asking me about his form, his attitude, and I said I would always take the best decision for the team,” said Conte. “I think, after this performance, I did make the best decision. The most important thing for us was for him to answer on the pitch.” Costa undoubtedly did just that.

His decisive intervention had actually come almost eight minutes into stoppage time at the end of an otherwise frustrating first half. Chelsea, for all their monopoly of possession, had run aground too often on Marco Silva’s well-drilled ranks with Hull’s resolve undisturbed even by the loss of Ryan Mason after a sickening clash of heads with Gary Cahill just after the quarter-hour mark. The former Tottenham Hotspur midfielder, a Chelsea supporter as a child, had received oxygen while lying prone on the turf undergoing treatment from members of both clubs’ medical staff. He departed on a stretcher and was rushed to the acute care unit at St Mary’s Hospital where he underwent surgery on Sunday evening having suffered a fractured skull. His recovery is Hull’s true priority.

Hull had reorganised impressively enough, only to be prised apart just as they were contemplating the break, and bemoaning the lack of a free-kick for Cahill’s tug back on Hernández. Victor Moses squeezed space away from Andy Robertson down the flank and pulled his centre back across the muddle of bodies in the six-yard box. Costa had held himself slightly back, easing himself away from Harry Maguire, and connected truly.

His side-foot shot flew in off Eldin Jakupovic’s left boot for a 15th league goal of the term. The celebrations, pinching thumb and fingers together with his hands lifted to his ears, presumably suggested there had been too much chat around the events of the last fortnight.

Such is the improvement in this Hull team under Silva that this was never a stroll thereafter, with the trip on Hernández surely worthy of a spot-kick had it been spied by the referee Neil Swarbrick or his assistant. Yet, while the impressive, marauding Maguire tested Thibaut Courtois from close range and long distance, the visitors finally yielded nine minutes from time. The substitute Cesc Fàbregas arced a free-kick into the six-yard box where another replacement, Oumar Niasse, mystifyingly ducked and Sam Clucas dawdled, allowing Cahill a free header from point-blank range. Conte had considered substituting his captain at the interval, such had been the severity of that clash with Mason. He ended up reserving his biggest bear hug of the day for the triumphant centre-back.

That gap from Arsenal in second place already yawns dauntingly wide for the chasing pack, with Chelsea having won 15 of their last 16 games and shed only 11 points all season. No one has been capable of hauling in their sprint to the summit. Their feat in accumulating 55 points after 22 games has been achieved only four times in the Premier League era, with this club contributing two of those eye-catching tallies under José Mourinho over a decade ago, and winning the title each time. Their next two games are against Liverpool and Arsenal, who both beat Chelsea in the autumn.

Emerge unscathed from those contests and it is hard to see anyone overhauling them over the campaign’s final three months, despite Conte’s insistence this division is capable of conjuring an upset. A weekend littered with unexpected results proved that much but Chelsea, bolstered by Costa’s contribution, merely watched others stumble. Their serene progress has been maintained.