Halting their winless streak in spectacular style, the Neroverdi put five past Milan at San Siro, while La Dea won again in the league before making a Coppa Italia exit in midweek.
Match preview
Even when Domenico Berardi teed up Gregoire Defrel to turn home Sassuolo's 19th-minute opener against Serie A's Scudetto-holders, few would have expected what was to follow in the next hour, as the Neroverdi laid waste to Milan's porous defence again and again.
Finding themselves 3-1 ahead at the break, courtesy of further strikes from Berardi and much-admired midfielder Davide Frattesi, the visitors went on to win Sunday's early kickoff 5-2 in the end - setting the tone for Monza's defeat of fallen giants Juventus later in the day.
Leaving the pitch with three assists also added to his record, Berardi has now been directly involved in 18 goals from 19 meetings with Milan, and the Italy winger will aim to continue such productivity against another Lombardy side this Saturday.
Success in the second city came as something of a surprise to most, even in spite of their hosts' faltering form, as Sassuolo had slid to just one place above the relegation zone - a run of two draws and six defeats from eight league games being the cause.
Having now secured a first away win since September, Alessio Dionisi's men aim to avoid losing three straight home fixtures in Serie A for the first time since 2019, when Roberto De Zerbi was still in charge. Incidentally, one of those three defeats came against Atalanta.
With a total of 11 wins from 19 league games versus Sassuolo, precedent as well as some impressive recent form is on La Dea's side this weekend - even if Atalanta did lose 2-1 on their most recent visit to the Mapei Stadium.
Only leaders Napoli have picked up more points than Gian Piero Gasperini's men so far in 2023, and they remain one of just three teams unbeaten this calendar year. Not only that, but they are also the division's top goalscorers since the winter break, with a tally of 17.
Their latest win came at the expense of struggling Sampdoria, as a goal in either half - from Joakim Maehle and red-hot forward Ademola Lookman - secured the Nerazzurri's 11th Serie A success of the season. By winning again in Emilia-Romagna, they would equal a club record of victories from the first 21 games - set both in 2016-17 and last year.
Some of the shine from such a start to the new year was tarnished on Tuesday, though, as Atalanta were knocked out of the Coppa Italia by regional rivals Inter - a failure to continue their goalscoring form saw them beaten 1-0 in the quarter-finals.
Also absent from European competition this term due to their second-half slump last year, Gasperini's goal of returning to the Champions League via a top-four finish now becomes La Dea's sole focus. As one of six teams with a chance of claiming that prize, however, they cannot afford to slacken their pace any time soon.
Sassuolo Serie A form:
L
L
L
L
D
W
Sassuolo form (all competitions):
L
L
L
L
D
W
Atalanta BC Serie A form:
L
D
W
W
D
W
Atalanta BC form (all competitions):
W
W
W
D
W
L
Team News
With Domenico Berardi back in the fold and fully firing after making only seven Serie A appearances in the first half of the season due to injury, Sassuolo coach Alessio Dionisi will also benefit from Davide Frattesi extending his stay until at least the summer - the latter has long been linked with a return to Roma.
However, Hamed Traore departed for Bournemouth before the transfer window closed, which creates a vacancy in the hosts' midfield: Maxime Lopez could therefore be recalled after a recent spell on the bench, while new arrival Nedim Bajrami is also in contention.
Gregoire Defrel and Agustin Alvarez again tussle for the right to start up front in Andrea Pinamonti's absence, though the latter may be passed fit in time to feature as a substitute.
Either striker's bullets will be provided by Berardi, who has now been directly involved in 176 Serie A strikes (105 of his own and 71 assists) since 2013 - only Ciro Immobile has racked up more during that time.
Atalanta, meanwhile, boast their own in-form forward, as Ademola Lookman - who scored the winner in October's reverse fixture - has netted 12 goals this season. In the 21st century, only five other players have recorded as many in the first 20 games of their debut campaign: Romelu Lukaku, Cristiano Ronaldo, Krzysztof Piatek, Diego Milito and Andriy Shevchenko.
By contrast, Duvan Zapata has struggled for form and fitness, having scored just once this term. The Colombian striker is now fully recovered from a hip problem and has previously scored nine goals against Sassuolo in his Calcio career, but Rasmus Hojlund may still start instead.
Jose Luis Palomino (thigh) and Davide Zappacosta (hamstring) remain injured though, and neither is expected to return until next week's clash with Lazio at the earliest.
Sassuolo possible starting lineup:
Consigli; Ruan, Erlic, Ferrari, Rogerio; Frattesi, Lopez, Thorstvedt; Berardi, Defrel, Lauriente
Atalanta BC possible starting lineup:
Musso; Toloi, Djimsiti, Scalvini; Hateboer, De Roon, Koopmeiners, Maehle; Lookman, Boga; Hojlund