Juventus have won the race for Matthijs de Ligt and handed Maurizio Sarri an €85.5million asset set to immediately challenge for a starting spot.
The Netherlands international commanded the attention of Barcelona, Bayern Munich, Manchester United and more before agreeing a five-year contract in Turin.
De Ligt, 19, captained Ajax with distinction in Europe and the Eredivisie last term and compiled a set of statistics consistent with a player who could change the look of Serie A's strongest defence.
Our dive into the Opta data illustrates why one half of Juve's established centre-back pairing might be looking over his shoulder.
Bonucci battle brewing
De Ligt has walked through the doors at Allianz Stadium in rather more triumphant fashion than Leonardo Bonucci did almost 12 months ago.
The Italy international returned from an ill-fated stint at AC Milan and resumed his partnership with Giorgio Chiellini at the heart of the four-man defence regularly employed by Massimiliano Allegri.
The results were not as intended.
Juve conceded more goals – 30 – in Serie A than in any of their previous seven title-winning campaigns, and were breached twice in the Champions League on four separate occasions.
De Ligt could apply serious pressure to the 32-year-old's position.
New boss Sarri favours a 4-3-3 system and his shiny new acquisition outperformed fellow right-footer Bonucci in most key defensive measures last term.
Across all competitions, De Ligt won more duels (5.48), aerial contests (3.77) and tackles (0.61) per 90 minutes, while also completing a greater average number of clearances (3.95) and recoveries (6.53).
Dwarfed in each category by the Dutchman, Bonucci ranked last behind Chiellini, Daniele Rugani and the now-retired Andrea Barzagli for duels (3.02), aerial contests (1.75) and clearances (2.86).
Aerial prowess an alternative weapon
Sarri's Chelsea were accused of being a one-dimensional team that sought only to break opposition sides down through often tedious passing sequences.
Alvaro Morata and Gonzalo Higuain floundered in their attempts to spearhead the front three and the Blues scored the fewest goals of all top-six sides in the Premier League.
Tormenting defences domestically should be no trouble for Cristiano Ronaldo, Paulo Dybala, Moise Kean and Juve's high-class attacking cohort, but Sarri would be wise to seek out a variety of scoring sources for an assault on multiple fronts.
In De Ligt, he has an aerial ace capable of climbing above any pack.
The 19-year-old conjured seven goals for Ajax last season: three in the Eredivisie, one against rivals Feyenoord in the KNVB Beker, and a further three in the Champions League.
Six of those were headed, including the towering effort which knocked Juve out of Europe while he also nodded an equaliser for Netherlands in their Nations League victory over England.
Bonucci, scorer of three goals, was the only Bianconeri defender to manage more than two.
Crucial interventions in big matches could tip the selection scale in De Ligt's favour.
Durability threatens established order
In the wake of Barzagli's retirement and the end of Martin Caceres' short-term loan, Juve reinforced their defensive stocks by signing Turkey international Merih Demiral from Sassuolo.
The 21-year-old will almost certainly find his place in the pecking order behind Rugani, a favourite of Sarri's since their time together at Empoli.
Bringing in a fifth centre-back to compete for one of two positions could lead the Italian champions to consider replenishing a diminished bank balance.
Paris Saint-Germain and Manchester City have reportedly shown interested in Bonucci, whose future is at least less certain than that of captain Chiellini.
What is in no doubt is De Ligt's readiness to carry the load required of a regular starter.
Throughout a demanding 2018-19 season, the reigning Golden Boy award winner turned out more times (55) than Chiellini and Rugani combined. Bonucci, Juve's top appearance-maker, started 14 fewer games.
Sarri demonstrated appreciation for a high degree of availability as he consistently paired David Luiz and Antonio Rudiger together at Stamford Bridge until a knee injury removed the latter from calculations.
Now, armed with hard evidence of De Ligt's excellence, the Bianconeri boss might forge a fresh partnership in Turin to herald the beginning of a new era.