Sassuolo missed the chance to go second in Serie A after being held to a 0-0 draw at 10-man Roma on Sunday.
Both teams had a goal ruled out after Roma forward Pedro was sent off four minutes before halftime following a second yellow card.
Sassuolo remained fourth, two points below second-place Inter Milan and four points behind league leader AC Milan, which visits Sampdoria later.
Roma is a point behind Sassuolo. Both teams could be overtaken by Napoli if it wins at last-place Crotone later.
It is Sassuolo’s eighth season in the Italian top flight and the team has never finished higher than sixth. But it got off to a great start this campaign and was looking to bounce back after its first defeat of the season last week at Inter.
There were few scoring opportunities but Roma thought it had taken the lead on the stroke of halftime and shortly after going down to 10 men. Henrikh Mkhitaryan’s goal was ruled out for a foul by teammate Edin Džeko on Sassuolo midfielder Manuel Locatelli.
Džeko almost redeemed himself after the break but his effort was deflected onto the right post.
Sassuolo substitute Lukáš Haraslín came close to breaking the deadlock moments after coming onto the field but he was marginally offside.
Hellas Verona drew 1-1 at home to Cagliari in a scrappy but entertaining match amid heavy rain in the north of Italy.
The weather also caused Atalanta’s match at Udinese to be postponed because of a flooded field.
Parma drew 0-0 against Benevento.