Inter Milan's Champions League hopes suffered a huge blow as Sassuolo shocked them again at the San Siro in Serie A on Saturday.
Sassuolo held on for a 2-1 victory to win away to Inter for the third year running.
Matteo Politano put Sassuolo ahead with a clever 25th-minute free kick which went under the jumping Inter wall.
Domenico Berardi almost doubled the lead, but Inter were frustrated when Mauro Icardi's effort was disallowed for offside just before half-time.
Icardi was also denied by a brilliant Andrea Consigli stop and Berardi extended Sassuolo's advantage after 72 minutes.
Rafinha pulled one back 10 minutes from time, but Inter could not find an equaliser in a frantic finish although, in truth, a draw would probably not have been enough for their top-four ambitions.
Defeat means Inter remain two points behind fourth-placed Lazio having played a game more.
Lazio will secure fourth spot and Champions League football by winning at Crotone on Sunday, while Sassuolo's win takes them above Genoa into 11th place.