He didn't really, though, and his squad remains largely familiar to the one that he inherited from Andrea Stramaccioni. There were moves here and there, mainly for promising youngsters, but on the whole, the squad felt largely familiar, which seemed a suicidal move. Inter conceded 57 goals last season, were horrifically disorganised and lacked for an identity. Stramaccioni's inexperience showed: the team slumped to a ninth place finish, the worst since 1994. Having won the Champions League amongst a historic treble in 2010, it represented a nadir.
Ground zero, then, maybe, not in personnel but in approach. "Let's say that we're working on things that in theory we should already know," goalkeeper Samir Handanovic explained. "We've started again from the ABC of football and defensive organisation. That's what we needed."
Such stripped-down training methods also apply to Inter's conditioning, which in marked contrast to the now commonplace use of small sided games for fitness, consisted of lots of basic running and sprints training. It was a throwback to an era gone by, and might have enraged sport scientists across the globe - but it delighted the fans, who felt it showed the team's dedication towards turning things round.
It's showed on the pitch, too, with a marked increase in team spirit obvious, and even less tangibly but still palpable, improved fitness levels - somewhat illustrated in Jonathon's energetic, powerful run to meet Ricky Alvarez's cross for Inter's 85th minute equaliser last night against Fiorentina.
The identity of scorer and provider was fitting. Alvarez struggled to justify his €11.75 million price tag last season, no thanks to fluctuating form and cruel cruciate ligament injuries. The sale of Wesley Sneijder, and then Antonio Cassano in the summer, meant Alvarez was one of the last proper creative players left at the club - but he's risen to the challenge as the no.10 in Mazzari's 3-5-2 formation.
Tucked in just behind Rodrigo Palacio, his nominal position is somewhat of a misnomer, as he frequently works the breadth of the pitch, drifting constantly to either side and creating the natural width high up the pitch that is absent from the formation. Typical of his varied positioning throughout the match, it was from a wide left position from which he won the corner for Inter's first goal against and Fiorentina, and then created the winner.
It's also typical of what has been a superb season to date, coming off the back of impressive performances in Inter's 7-0 romping over Sassuolo, as well as the 1-1 draw with defending champions Juventus. An interesting feature of those games has been his tendency to take players on often by simply knocking the ball into space beyond them - as simple as it sounds, it helps drive counter-attacks upfield quickly, and there was a good example against Fiorentina when Alvarez dribbled past Massimo Ambrosini in a one-on-one on halfway, leading to a 3v2 attacking situation in favour of Inter.
Jonathon, meanwhile, was never even meant to be in this team. One of Mazzari's clear targets in the transfer window was clearly a right-sided wingback: loanee Wallace from Chelsea was a stopgap in light of the failed pursuits for Mauricio Isla and Juan Zuniga. It seemed like Mazzari didn't trust Jonathon enough, but the Brazilian has proved an able fit for the right wing-back position - after an initial period of conservativeness going forward, he's now frequently flying forward, replicating the like-minded movement of Yuto Nagatomo on the opposite flank.
Intriguingly, he's not been the only one providing width and directness down the right flank. Hugo Campagnaro, the one player Mazzari brought with him from Napoli and whom who he has spent seven years working with (having also both been at Sampdoria), completed the second most passes in the attacking third against Fiorentina (behind Jonathon), illustrating his somewhat paradoxical attacking intent.
After all, Campagnaro is the right-sided centre-back in the back three, and although the outside defenders in that particular formation have a little more freedom to get forward, it's certainly unusual to see one, at times, becoming the most advanced attacker. The combination between him and Jonathon was certainly encouraging (and accounted for the two highest pass combinations against Fiorentina, revealing the frequency of which they linked up), but even more so is the cohesion between the back three - which has played a significant role in Inter's surprising defensive stinginess.
They spread themselves out nicely when in possession, which makes it easy to pass out under pressure, but importantly, became very narrow and compact when without possession, making it difficult for opposition defences to play through. The presence of three strong, physical midfielders - Fredy Guarin, Esteban Cambiasso and Saphir Taïder - in front of them also helps. Fiorentina dominated possession, with Borja Valero and Alberto Aquilani enjoying lots of time on the ball, but rarely found an incisive pass.
In fairness, though, Inter have had previous experience in a 3-5-2, with Stramaccioni using the formation extensively throughout the ultimately doomed 2012-13 campaign. The difference now is that the players understand their roles - the manager isn't just switching shape to shoehorn his best players into the team - and that the new 3-5-2 is the result of a long, ongoing process throughout pre-season to, as Handanovic put it so well, "relearn the basics."
They're not quite coming from ground zero, but Inter are certainly on the up.