Nothing had changed, and yet everything had changed. The team who started the weekend top of the table were still top of the table. They were still the reigning champions, still the front-runners – with more points and a better goal difference than anyone else – and still heavily favoured by the bookies to retain their title. Juventus were, in other words, still the team to beat. But they were no longer a team who could not be beaten.

By the time they faced Internazionale on Saturday, Juventus had gone 538 days without a league defeat. In that time they had moved into a new stadium, appointed Antonio Conte as their manager and signed Andrea Pirlo. They had gone from being a side which finished seventh, missing out on even the Europa League, in 2010-11 to one that claimed the Scudetto 12 months later. In total their unbeaten run extended to 49 Serie A games.

Now they had the chance to complete the half-century against one of their oldest and greatest rivals. Inter may not share a city with Juventus, but the clubs' distaste for one another was sufficient already by the 1960s for the legendary journalist Gianni Brera to coin the phrase "Derby d'Italia" for matches between the two. The mutual enmity had only been heightened in recent years by the fall-out from the Calciopoli scandal of 2006.

A fixture that was always going to be keenly felt – the Juventus goalkeeper Gigi Buffon admitted afterwards that "this was the one we wanted most of all" – was rendered even more meaningful by its context. Beyond the desire to extend their unbeaten run, Juventus also knew that Inter were potential contenders for the title.

Where Napoli – previously viewed as Juve's most likely challengers – had stumbled since losing to the Bianconeri in Turin last month, Inter had put an indifferent start behind them to become Serie A's form team. By the time Saturday's match rolled around the Nerazzurri were up to second in the table, just four points behind. They had won their last eight games in all competitions, as well as all eight of their away games so far this season.

Inter's team selection spoke to the confidence of their young manager, Andrea Stramaccioni. The inclusion of the forwards Diego Milito, Antonio Cassano and Rodrigo Palacio together in the starting XI did not suggest a team that had come to defend. Stramaccioni had insisted in his pre-match press conference on Friday that he set out only to win games, not draw them, and here was evidence of that commitment.

It would take less than 20 seconds on Saturday for that self-belief to be strongly tested. That was as much time as it took for the Juventus midfielder Arturo Vidal to open the scoring – slotting Kwadwo Asamoah's square pass into an unguarded net.

Already, the narrative for this game looked set. Asamoah had been in a clear offside position when he first received the ball inside Inter's half, yet the linesman Fabiano Preti's flag stayed down. Just as two weeks earlier in a controversial win over Catania, Juventus had been the beneficiaries of a critical blown call. But that was just the beginning.

For the next 10 minutes Juventus were rampant, Stramaccioni's apparent naivety exposed as the hosts sliced through a poorly protected Inter back line. Only a fine stop from Samir Handanovic prevented Claudio Marchisio from extending their lead. When Inter did finally break, Palacio had a goal disallowed for offside. It was the right decision, though the margins were much more fine than they had been with Asamoah.

Another genuine injustice would arrive before half-time, however, Stephan Lichtsteiner inexplicably avoiding a second yellow card after chopping down Palacio. Juve's assistant manager Angelo Alessio – filling in for Conte on the bench during the latter's touchline ban – ensured that this pardon did not go to waste by immediately replacing the defender with Martín Cáceres.

This was the point at which Inter might have been expected to lose their heads – reasoning themselves to be the victims of a stitch-up and pouring their energies into protest rather than response. And yet they did not. Instead Milito got them level, converting a penalty early in the second half after having his shirt pulled inside the box by Marchisio.

The tide had turned. Stramaccioni withdrew an exhausted Cassano for the midfielder Fredy Guarín, but despite a change in shape his team's attacking intentions were undiminished. It was the substitute whose fierce drive was parried by Buffon with a quarter of an hour to go, only for Milito to force the rebound home. Fifteen minutes later, with the hosts chasing an equaliser, Palacio added a third on the counter.

Just like Arsenal in October 2004, Juventus had seen their unbeaten run end at 49 matches. "Now Juve know who the anti-Juve are," Luigi Garlando would write a day later in La Gazzetta Sportiva. "It is this possessed Inter team who desecrated their front room … and made them feel the bitterness of defeat."

For Inter, after a ferociously contested game, the release of nervous tension was almost too much to take. "I'm giving birth," joked Cassano's pregnant wife on Twitter. The forward himself leapt on his manager's back and clung on for dear life as they were drowned in a sea of delirious colleagues.

The players had performed their tasks exceptionally, but this felt like a victory of the manager's making – from the bold selection through to his calm reaction to the various injustices that befell his team. Where his predecessor José Mourinho had once demonstrated his unhappiness at decisions by this same referee, Paolo Tagliavento, with his infamous "handcuffs" gesture. Stramaccioni slapped the wall of his dugout at one point but otherwise largely kept his composure.

His refusal to descend into rage or self-pity was reflected in the way his players stuck to their task, breaking Juventus down through sheer persistence. Tactically, too, his schemes were a success – the nuance to his seemingly attacking selection revealed as Milito and Palacio repeatedly dropped deep to close down Pirlo and deny him room to work with.

Inter might not have been the only ones relieved to see his schemes pay off. After the outcry that followed Juventus's win over Catania, the last thing the league would have wanted was for this most high-profile of fixtures to have its final result similarly conditioned by incorrect decisions.

"They ought to make a monument to Stramaccioni," Alessandro Vocalelli would write in La Repubblica a day later. "Above all [the Italian Football Federation president Giancarlo] Abete, [the Italian Referees' Association president Marcello] Nicchi and all those in a position of power in football ought to make a monument, because after that first minute, a lot of people could have been embarrassed and some might have done well to start writing letters of apology and resignation."

Stramaccioni himself declined to speak about the referees – something he has tried to make a point of doing. "If I speak about this I will be breaking my word," he said. "I do not speak about referees."

It was one of a number of admirable lines from a manager who – despite one or two digs at the opposition – continues to come across as admirably humble. From day one his obsessive preparation and confident manner have earned comparisons with Mourinho, but Stramaccioni will have no part of such talk. "I am not the Special Two, I am just a young manager who wants to learn," he said. "I always prepare every match as if it was my last."

Instead he credits Massimo Moratti for taking a chance on a man who is, after all, three years younger than the team's captain, Javier Zanetti. The Inter president speaks in just as glowing terms about his employee. "I am not surprised by the result," said Moratti. "Before the match, our manager explained to me [how his tactical plan would work] – and things then unfolded in exactly the way he described. Our team did word for word what it was supposed to do."

If that makes it sound routine, then the reality was anything but – Stramaccioni achieving something that nobody else had managed in 49 tries. Even Mourinho never managed with Inter to beat the Bianconeri in Turin – and that was before Juventus Stadium had even been completed.

And so Juve are left to lick their wounds – falling nine games short of the Serie A record of 58 consecutive games unbeaten achieved by Milan under Fabio Capello between 1991 and 1993. But with Conte's suspension nearing its end, they remain a point clear at the top of the table. Only time will tell if this was the weekend when everything really did change – or in fact nothing at all.

Talking points

• Catania took out the residual frustration from their own contentious defeat to Juventus last week with a stunning 4-0 rout of Lazio. "It's not the Camp Nou, but the Massimino," read the match report in Il Messaggero. "A stadium where life is difficult for every visitor." Catania's home form is indeed impressive –Juve are the only away team to have won there. But Lazio's slipping performances are also a worth noting. In the three-and-a-half games since Miroslav Klose put the team 3-0 up against Milan on 28 October, Lazio have conceded nine goals and scored just one.

• Catania were not the only ones to win by four goals this weekend, Milan putting their recent struggles behind them in a 5-1 demolition of Chievo. A more positive afternoon for the Rossoneri is hard to imagine. Bojan Krkic got his first goal for the club and Giampaolo Pazzini his first since 1 September. Stephan El Shaarawy – presently Serie A's leading goalscorer – got his eighth in as many league games. Even Kevin Constant put in a respectable shift as a makeshift full-back. "I don't believe that another club in the same situation as us would have defended their manager like we have," said the team's vice-president, Adriano Galliani, afterwards. It will take a few more results like this yet before all fans are convinced that his faith in Massimiliano Allegri is a good thing.

• Zdenek Zeman was more circumspect after watching his Roma team beat Palermo 4-1, noting that "we must not think we have solved all of our problems". Palermo presented only modest opposition, but certainly it was encouraging to see the Giallorossi press home an advantage for once. The only black mark on this day was Mattia Destro receiving a red card that means he will now miss next week's Rome derby. The forward had only been on the pitch for seven minutes – but had already picked up a booking before scoring his first ever goal for the club. He began to take off his shirt to celebrate before thinking better of it, but the referee Andrea De Marco showed him the second yellow anyway.

• Fiorentina triumphed by the same margin at home Cagliari, moving up to fourth in the division. This was not a result to be taken lightly against a side who had won four in a row under their new management team of Ivo Pulga and Diego Lopez. With Lazio faltering and Napoli also dropping points at home to Torino – Salvatore Aronica's lacksadaisical backpass letting Gianluca Sansone in for an injury-time equaliser – Vincenzo Montella's team are only two points off third and beginning to look like they might belong among the leading pack.

• It has been a rather less positive time for the city of Genoa, with Sampdoria falling to their sixth consecutive defeat and Genoa their fourth. "Real men come out of these situations," said the Samp manager Ciro Ferrara after his team's home defeat to Atalanta. "And I know I have a group of serious guys here."

Results: Bologna 1-1 Udinese, Catania 4-0 Lazio, Fiorentina 4-1 Cagliari, Juventus 1-3 Inter, Milan 5-1 Chievo, Napoli 1-1 Torino, Pescara 2-0 Parma, Roma 4-1 Palermo, Sampdoria 1-2 Atalanta, Siena 1-0 Genoa.

The current Serie A table