With 86 minutes gone of their last Serie A home match AC Milan's title defence was very much alive, two goals to the good against Roma and set to maintain the five-point gap separating the champions and league leaders Napoli.
Less than three weeks later and their hopes of retaining the Scudetto are hanging by a thread after a sudden slump which has allowed Napoli to charge 12 clear almost completely unopposed, and led to them being knocked out of the Italian Cup and losing the Super Cup to Inter Milan.
Two quickfire goals from Roger Ibanez and Tammy Abraham snatched a shock draw for a dismal Roma that night at the San Siro, and since then Milan have looked a shadow of the team who last year snatched the title from neighbours Inter.
The partying which exploded last Spring in celebration of Milan's first league crown since 2011 felt like a distant memory on Tuesday night when Lazio demolished Stefano Pioli's side 4-0 and moved a point behind them in third place.
Pioli all-but conceded the title after a miserable display in Rome, admitting that "right now a lot of things aren't working" as previously reliable performers either get injured or underwhelm on the field.
Director Paolo Maldini insisted on Tuesday that the season "doesn't seem like a huge disaster" but the Milan icon has been criticised for flop summer signings including Belgium attacker Charles De Ketelaere and Sergino Dest, whose display on Tuesday at left-back in place of injured Theo Hernandez was calamitous.
On Sunday Milan host struggling Sassuolo -- the team whose ground fans invaded en masse to witness a long-awaited title triumph in May -- the perfect opportunity to set their season back on course.
But it would take a complete implosion for Napoli to let slip a historic first title since 1990, after racking up an incredible 50 points at the halfway stage of the season.
Napoli host fierce rivals Roma for the first time since a huge dust-up between hardcore fans of both teams caused a motorway to be closed for nearly an hour while Roma supporters travelled to their dramatic draw with Milan.
There will be no one in the away end at the Stadio Maradona on Sunday night as both sets of fans were banned from travelling for two months in the wake of that fight.
Roma, like Lazio and Inter Milan, are a point behind Milan and have a promising strike partnership forming between England international Abraham and Paulo Dybala.
But coach Luciano Spalletti knows his team have a "potentially once-in-a-lifetime opportunity" to end over three decades of waiting for southern Italy's biggest club, who will likely have Khvicha Kvaratskhelia back after the Georgian wing wizard recovered from flu.
Meanwhile Juventus continue their bid to rise back up the table, following a brutal 15-point punishment for illicit transfer activity, when they host surprise package Monza in Turin.
Massimiliano Allegri said last week that Paul Pogba and Dusan Vlahovic would be available for selection, and fans are wondering when France midfielder Pogba will finally turn out for the Turin giants after a knee injury nightmare cost him the World Cup and the first half of the domestic season.
What to watch out for: SAOT
Semi-automated offside technology (SAOT) will make its Serie A debut this weekend after being used at the World Cup and the group stage of this season's Champions League.
Italy's top flight will become the first major domestic league to implement the technology this weekend, in the hope it will end rows like the one in September after Juventus' winning goal against Salernitana being ruled out because VAR cameras somehow didn't spot Antonio Candreva standing by the corner flag, playing everyone onside.
Fixtures (times GMT)
Bologna v Spezia (1830), Lecce v Salernitana (1945)
Empoli v Torino (1400), Cremonese v Inter (1700), Atalanta v Sampdoria (1945)
AC Milan v Sassuolo (1130), Juventus v Monza (1400), Lazio v Fiorentina (1700), Napoli v Roma (1945)