Would it be too dramatic to portray a November missed penalty as a sign to let go of everything we thought we knew about the Serie A title race? Well, yes, OK, probably it would. But seeing Hakan Calhanoglu’s spot-kick carom back off a post in the second-half of Inter’s 1-1 draw with Napoli was at the least a shock to the system.

He had converted all his previous 19 attempts since joining the Nerazzurri from Milan in 2021. “It had to happen sooner or later,” said the player. Were the rest of us ready, though, to live in a world shorn of such certainties? As the commentator Patrick Kendrick put it: “With Calhanoglu missing, we’re just left with the misery of death and taxes”.

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That, and a fierce fight for position among the division’s pace setters. Inter, the reigning champions, had hoped to overtake Napoli and claim the leaders’ jersey. A draw kept them trapped in the middle of a breakaway group instead. After 12 games, Serie A’s top six teams are separated by only two points and have started to pull ahead of the rest of the pack.

More on that later. Scott McTominay’s 23rd-minute goal from a corner forced Inter to chase this game. No small task, against an Antonio Conte team who had already collected seven clean sheets. Yet Calhanoglu brought them level with a sensational goal before half-time, taking advantage of standoffish defending to line up a 25-yard drive that swerved away from the goalkeeper Alex Meret.

Inter looked poised to go on and win. Their hunger to do so had been apparent already from the midweek selection to face Arsenal, Simone Inzaghi giving Champions League rests to Marcus Thuram, Nicolò Barella, Federico Dimarco, Henrikh Mkhitaryan and Alessandro Bastoni. Depth is this squad’s greatest strength, but the side that faced Napoli was far closer to a first-choice XI.

Dimarco hit a post at the start of the second half, and drew a further save from Meret, before Inter were awarded their penalty with just over a quarter of an hour left to play. Frank Zambo Anguissa’s boot caught Denzel Dumfries’s shin as the pair challenged for a ball. The contact was light, but the referee Maurizio Mariani had a clear view.

It felt like game over for Napoli. Giving Calhanoglu the chance to beat you from 12 yards has been a more reliable path to defeat than offering Elena Delle Donne a shot from basketball’s free-throw line. The Inter midfielder simply does not miss. Only this time, he did, slamming his shot against the left-hand upright.

The contest was not over. Barella called Meret into action again moments later, sidestepping a defender’s lunge but aiming too close to the keeper. A draw almost became a defeat for Inter when Cyril Ngonge crossed to fellow Napoli substitute Giovanni Simeone in injury time. The Argentinian hooked his shot over from six yards.

That late let-off could not ease Inzaghi’s frustration. “It leaves a bitter taste,” he said. “If the lads had not played as well as this, I might not have this bitter taste, but we had a great performance tonight against a strong opponent. Lots of teams who played in the Champions League have had problems.”

Lecce 1-1 Empoli, Juventus 2-0 Torino, Cagliari 3-3 Milan, Venezia 1-2 Parma, Inter 1-1 Napoli, Monza 0-1 Lazio, Roma 2-3 Bologna, Fiorentina 3-1 Verona, Atalanta 2-1 Udinese

A not-so-subtle reminder of the additional challenges his team faced, compared to opponents who missed out on Europe altogether. From the moment Conte was named as Napoli’s manager this summer, pundits have wondered whether the lighter calendar might aid him in restoring the Partenopei as title contenders. We have a long way to go yet, but the answer so far is a resounding yes.

Inter remain the favourites, having demonstrated last season how they are built to win marathons even more than sprints. Equally, we cannot dismiss the first third of a season as a fluke. Napoli have earned their position on top of the pile, and the impact of playing fewer games may only become more pronounced the longer this season goes, given the fresh expansions to the European calendar.

“There are a lot of games,” said Calhanoglu. “Really a lot. We don’t have time to stop and look at the table because every time we want to take a rest there’s another one to play. It’s not so hard physically. But mentally it’s not so easy.”

His team is not alone in facing such pressures. Every other top-six side – Atalanta, Fiorentina, Lazio and Juventus – is also competing in Europe besides Napoli. All but the Bianconeri are doing so with considerably smaller financial resources than Inter.

There was a hint of fatigue in Atalanta’s slow start against Udinese this weekend. They were fortunate not to concede a second-minute penalty when Isak Hien controlled the ball with an arm and grateful to their goalkeeper, Marco Carnesecchi, for keeping out a string of chances before finally letting one in from Hassane Kamara on the stroke of half-time. But they roared back in the second-half to win 2-1.

It felt like their season in microcosm. The Bergamo club collected just two wins and two draws from their first eight games across all competitions, struggling to adapt after losing Gianluca Scamacca and Teun Koopmeiners in August – the former to injury and the latter to a €55m Juventus move. Ademola Lookman was late to return to the fold after having his head turned by transfer talk, too.

Now they have taken eight wins from the last nine – a sequence interrupted only by a draw with Celtic. Atalanta beat Napoli 3-0 at the Stadio Maradona and have piled up 31 league goals already – five more than the next-most prolific side, Inter. After winning the Europa League in May, there is growing belief that Gian Piero Gasperini’s team could sustain a bid for the Scudetto.

That might be a more distant prospect for Fiorentina, though if Moise Kean can keep up his strike rate of one goal every 114 minutes, who knows? Like Atalanta, the Viola have won six league games in a row – a run that has seen them thrash Roma 5-1 and Lecce 6-0. Raffaele Palladino insisted he is not even looking at the table after this weekend’s 3-1 win over Verona, but if he did he would see his team have the same points and a better goal difference than Inter.

Marco Baroni’s Lazio have been less eye-catching but no less impressive. Their last 11 games have yielded 10 victories and a 1-0 loss in a game which they played a man down from the 24th minute. Mattia Zaccagni fired them past Monza this weekend. Juventus beat Torino 2-0, staying sixth while also extending their run as the last unbeaten team in the division.

It is hard to imagine that the race will stay this tight, that all of these teams can sustain the pace they have set. Then again, not so long ago, it was hard to picture Calhanoglu missing the target from 12 yards.