Juventus are favourites to make it seven Serie A titles in a row but their rivals are sniffing blood ahead of the Old Lady's Serie A opener versus Cagliari on Saturday.

AC Milan's remarkable transfer spurge – and one showpiece signing in particular – could have wide-reaching ramifications in Italy's top flight, where the stakes are raised by four Champions League places being on offer for the first time since 2010-11.

Video Assistant Referees (VAR) are also on the agenda, while SPAL are back in Serie A after a 49-year absence and recently averting financial ruin.

Here we look at some of the major issues on the table as Massimiliano Allegri's Juve aim to preserve their dynasty.

Milan clubs aiming to re-establish 'big three'

Andrea Pirlo's move from then-champions Milan to Juventus in 2011 is often viewed as a watershed moment for the modern Serie A, a transfer that kick-started an on-going stranglehold. The potential parallels are not lost on Leonardo Bonucci after his stunning €42million move from Turin to San Siro. "I hope to do with Milan what Pirlo did with Juve," the Italy international, who has a strong claim over being the world's premier centre-back, told Gazzetta dello Sport.

Shouldering such lofty ambitions, Bonucci is unquestionably the most eye-catching acquisition among an outlay in excess of €200m that also includes he likes of Andre Silva, Franck Kessie, Hakan Calhanoglu, Ricardo Rodriguez and Andrea Conti.

Silva scored twice at a buoyant San Siro as Vincenzo Montella's impressively retooled squad hammered Shkendija 6-0 in the Europa League in midweek and the major source of intrigue ahead of their Serie A opener at Crotone is how much owner  Li Yonghong's rampant ambition will be rewarded on the field.

Milan only need to look to neighbours Inter to see how an ambitious spending programme might not reap immediate dividends. The Nerazzurri limped to seventh last term despite the lavish backing of the Suning Group – Frank de Boer and Stefano Pioli both losing their jobs as head coach after Roberto Mancini departed on the eve of the campaign.

Luciano Spalletti appears to have steadied the ship if friendly wins over Chelsea, Villarreal and Bayern Munich are anything to go by, while apparently warding off Manchester United's interest in influential winger Ivan Perisic is a huge boost. Like their old rivals, a top-four spot feels like a must for Inter this time around.

Seventh heaven or back to earth for Juventus

Allegri was Milan coach when Pirlo made his fateful move and it would not be a good look for him if Bonucci's departure heralds another sea change.

The key question surrounding Juventus is precisely how deep the scars from their chastening 4-1 Champions League final defeat to Real Madrid are. Bonucci and Dani Alves have left the club amid strenuously denied allegations of dressing room unrest at the Cardiff showpiece.

Juve's return to competitive action was far from encouraging as they lost 3-2 to Lazio in the Supercoppa Italiana – Paulo Dybala's late brace to launch a brief and swiftly extinguished comeback obscuring a largely abject showing that led Allegri to label his players as "pushovers".

Neverthless, the deck is still heavily stacking in Juve's favour as goalkeeping great Gianluigi Buffon gears up for his final season. The ever-improving Dybala has been largely absent from talk over how Barcelona might spend their Neymar bounty, while Douglas Costa and Blaise Matuidi stand as shrewd, high-end reinforcements. They remain, unquestionably, the team to beat.

Free-scoring Napoli and Roma target fresh title tilt

Milan's sixth-place finish last time around was their best in four seasons, underlining the distance the emboldened Rossoneri must travel to rule Italy once more. Indeed, if Bonucci's departure proves a major hindrance to Juventus, it might be Napoli who are best placed to capitalise.

Maurizio Sarri's swashbuckling side only lost once in Serie A after October last season and were the division's top scorers, with 94 to Juventus' 77. Dries Mertens revelled prolifically in the extra goalscoring responsibility sent his way due to Gonzalo Higuain joining Juve and Arkadiusz Milik suffering knee ligament damage.

Belgium international Mertens got up and running this time around in Wednesday's 2-0 Champions League play-off win over Nice. He missed out on the Capocannoniere by one goal, with Roma's Edin Dzeko netting 29 of his club's 90 to Mertens' 28.

Similarly, Roma finished a point and a place above Napoli in second, although a close-season of significant changes at the Stadio Olimpico means their title hopes are more of an unknown quantity.

Spalletti's departure to lead Inter underlined how the traditional clout of the Milan clubs remains undimmed despite their recent struggles, while Francesco Totti's emotional retirement means Roma are into a new era before the freshly minted alliance between director of football Monchi and head coach Eusebio Di Francesco is considered.

Antonio Rudiger and Mohamed Salah's departures to the Premier League look like significant blows and Monchi will hope the arrivals of Lorenzo Pellegrini, Rick Karsdorp, Aleksandar Kolarov and Turkish sensation Cengiz Under show he has not lost his Midas touch from Sevilla.

SPAL back from the brink in fairytale return

If Milan are looking for omens to bolster their pre-season enthusiasm, they were champions and UEFA Cup Winners' Cup winners the last time SPAL featured in Serie A.

That was back in 1967-68 and one of Italy's oldest clubs have since subsided in the lower tiers, hamstrung by financial woes. The most recent crisis came in 2013 when they merged with neighbouring fourth-division side Giacomense to avoid going out of business.

Head coach Leonardo Simplici guided them to Serie B and SPAL made it back-to-back promotions last season. How the former Fiorentina youth coach's expansive 3-5-2 fares in the top flight remains to be seen but their visit to Lazio on Sunday is sure to be an emotional occasion.