Sassuolo scored three goals in the first half-hour as they beat fourth-placed AS Roma 4-2 in Serie A on Saturday, their first-ever win against the club from the capital.
Mid-table Sassuolo had drawn five and lost eight of their previous 13 meetings with Roma but never looked back after striker Francesco Caputo stunned the visitors with two goals in the first 16 minutes.
Caputo broke clear to sweep the ball past Pau Lopez in the seventh minute, then finished off a slick passing move by turning in Jeremy Toljan's pass nine minutes later.
It got worse for Roma as Filip Djuricic latched onto Domenico Berardi's pass to place the ball past Lopez for the third after only 26 minutes.
Edin Dzeko headed one back for Roma in the 55th minute but they suffered another blow with Lorenzo Pelligrini's dismissal for a second bookable offence in the 69th minute.
Even so, Roma pulled one back four minutes later with a Jordan Veretout penalty after Jeremie Boga naively handled a cross. However, the French-born Ivorian forward immediately made amends by breaking clear to curl in Sassuolo's fourth goal one minute later.
Roma, with 39 points, will lose their top-four place if Atalanta, who are one point behind, beat lowly Genoa on Sunday.
Parma twice came from behind to draw 2-2 at Cagliari, scoring their second equaliser in the fourth minute of stoppage time to leave both teams with 32 points with the Sardinians ahead in sixth place on their head-to-head record.
Joao Pedro turned in Giovanni Simeone's cross in the 19th minute for Cagliari and Juraj Kucka levelled three minutes before the break. Joao Pedro missed a penalty seven minutes after halftime, Simeone spared his blushes by scoring in the next attack and Andreas Cornelius headed a last-gasp equaliser.
Mattia Bani scored an 89th minute goal, turning in Musa Barrow's cross at the far post, to give ninth-placed Bologna a 2-1 win over relegation-threatened Brescia in the early game.
Ernesto Torregrossa put Brescia ahead with a penalty in the 36th minute against the run of play and Riccardo Orsolini levelled with a shot on the turn two minutes before halftime.