Looking at the standings and statistics after eight games, Sunday's match between Milan and Sassuolo shouldn't be an uncertain match. The Neroverdi have 15 points, 11 goals and a plus-3 goal differential, while the Rossoneri have only 10 points—ranking 13th in Serie A—a minus-5 differential and eight goals. Sassuolo has been playing consistently since the beginning of the season despite its unbalanced system showing it is getting better than the last two seasons.
Eusebio Di Francesco has always been an offensive-minded manager, due to his experience as a player at Roma, when he was coached by Zdenek Zeman. Sassuolo is the perfect concretization of this mentality. For that reason, it's ideal formation is—and will always be—a 4-3-3 with a wide offensive line made by quick and skilled players, like Antonio Floro Flores (or Gregoire Defrel) and Domenico Berardi (or Nicola Sansone) that can attack toward the center. This offensive mentality can be applied if the team is athletically ready to run up and down the field for an entire game, and that's actually what they do, as you can see from the interactive graphic below.
Serie A km/game ranking (data source: legaseriea.it)
Despite the big improvements made in the last two seasons, the team is still a bit unbalanced due to the lack of quality at midfield but Di Francesco has—almost—no other options, besides Francesco Magnanelli, Davide Biondini and Simone Missiroli in that position and the team is slowly adapting to that situation. On the other hand, they have Berardi who has been a real nightmare for Milan's defenders, scoring seven goals in the last two seasons against the Rossoneri.
Sassuolo's starting lineup according to La Gazzetta dello Sport.
Roster & Roles
Goalkeepers: Andrea Consigli, Gianluca Pegolo, Alberto Pomini, Bryan Costa.
Defenders: Francesco Acerbi, Luca Antei, Lorenzo Ariaudo, Paolo Cannavaro, Marcello Gazzola, Alessandro Longhi, Federico Peluso, Emanuele Terranova, Sime Vrsaljko, Claud Adjapong, Martin Erlic, Leonardo Fontanesi.
Midfielders: Davide Biondini, Francesco Magnanelli, Simone Missiroli, Lorenzo Pellegrini, Karim Laribi, Alfred Duncan, Daniele Cipolla, Geremy Tonye.
Forwards: Domenico Berardi, Diego Falcinelli, Sergio Floccari, Antonio Floro Flores, Matteo Politano, Nicola Sansone, Marcello Sereni, Nicolò Bruschi, Nicola Zanini.
Sassuolo's only alternative to the starting trio at midfield is Alfred Duncan, since Laribi is more a trequartista than midfielder, proving that Di Francesco is forced to make his forwards run a lot to keep the team balanced.
Once again, the tactical key for Sassuolo is balance: their defense is a bit slow, but it's still a solid line, especially thanks to Andrea Consigli and former Milan defender Francesco Acerbi; offensively they have two reliable wingers like Berardi and Floro Flores and plenty of options as a striker like Floccari, Defrel or Falcinelli; at midfield they can provide good coverage to the defense thanks to Magnanelli and Biondini, but they lack some technique.
Numerical superiority at midfield could be important against them.
As you can see from the graphics, if they don't put too much pressure on Milan's defenders, the Rossoneri will have the chance to keep the ball possession and make some plays starting from their half of the field. If Mihajlović decides to play with a 4-4-2 formation, Milan could even take advantage of its numerical superiority and threaten Sassuolo's defenders playing on the two wings. Also, Carlos Bacca and Luiz Adriano is the ideal starting duo as forwards since their combination of speed, physicality and technique could be a tough matchup for slow defenders like Acerbi and Cannavaro.